Friday, 28 December 2012

Plastic not so Fantastic: Water Bottle, Plasticizers and Surface Tension






I was in the lab yesterday and wanted to compare the surface tension of water from our MilliQ system and water that is in these plastic bottles.  I used the Kibron EZ-Pi Plus in static surface tension mode.  The surface tension of water is 72.8 mN/m.  This was the value from the MilliQ water.  However, when I did the same test with the plastic from the water bottle it lowered the surface tension to 71.0 mN/m.  These water bottles and other materials like a silicone septum may contain plasticizers, silicone or other surface active materials.  This leaching of these chemicals may cause false positives or add confusing results to when measuring surface active substances from drugs to lipid molecules.  Particular precautions should be made in order to limit the leaching from these bottles (eg. working with glass or ceramic, degassing water, working with the water touching the plastic within a small time period). 

Even if you do not work in a lab or care about surface active substances this result can still affect you.   You likely at some point have had a drink from a plastic water bottle at some point in your life.  Sure it has a nice little sticker printed on the front of it.  It says the it pours from some glacier you have never heard about.  It could also come from a local well that is said to be a fountain of youth.  It has a sealed cap.  It must be good stuff.  Anything that is branded has a name and is in my local market must be good.  Right? 



Wrong.  Even if the water is said to be pure, a plastic container may leach chemicals such as phthalates or bisphenol A (an industrial chemical linked to increased risk of birth defects, miscarriage, baldness and prostate cancer) into the bottled water. Scratches in the plastic, harsh detergents, and boiling liquids exacerbate the leaching. 




However,  tap water is probably better which in the end you are just buying in bottled form.  In the end some say that up to 40% of bottled water is tap water.  In addition some brands contain chemical contaminants at levels above strict state limits. If consumed over a long period of time, some of these contaminants could cause serious health problems.

What is the best water bottle to drink from?  For personal health, the ideal water container is glass. However, glass bottles are rare, heavy, and breakable. Many believe polycarbonate (PC) plastic is a good option due to its durability and lack of odor, but it can still leach bisphenol A into its contents and with a recycling code of number 7, is rarely recyclable. A better health option may be one of the new bio-based alternative plastics (such as those made with corn starch)—not really a plastic, but with similar properties, yet reusable and readily biodegradable.

If you can’t avoid drinking water from plastic bottles, make certain it has not been exposed to high temperatures, such as being left inside a locked up car or near a glass window. 0.001 ug/L with LC/MS.  However some of the degraded BPA may be present as well which might be just as harmful.  To find the total organic carbon.  Measuring surface tension will allow you to see if there are any of these leached substances quickly and easily. 

 

Tuesday, 18 December 2012

Oil Christmas Trees in Texas




Surface tension and other natural physical phenomenons has become a central way to make interesting artistic projects.  Ferrofluids, electromagnetism and surface tension create interesting art together.  Ferrofluids are oil laces with bits of iron oxide.  The iron allows this fluid to become magnetic when a magnetic field is applied.  Japanese artist Sachko Kodama turned her ferrofluid creation into a Christmas special that the people at Exxon or BP must love.  She probably noticed the effect of surface tension when she applied the field and realized there are branches like that of a Christmas Tree.  The surface tension of the oil causes the branches to pull into themselves forming sharp tips.  There is a spiral effect from the two towers which spray fluid out allows these Christmas trees to seem to blossom.

Maybe she is is trying to tell us something?  A relationship between oil and the life blood of Christmas or that humans do not value living things anymore but oil is more important.  Or maybe she just saw a cool effect with surface tension and electromagnetism to show through art.


Check out her site she has some really cool stuff using ferrofluids and other physical properties.

Monday, 10 December 2012

Shake it, shake, shake, shake it: Getting from wet to dry

We are all limited by the physics around us so we have to adapt in order to get things done.  In this case the getting thing done is getting water off of your body.  If left on the body water can collect dust, form mildew, provide unwanted heat exchange among other things.  So it is essential for mammals to get dry.  Water has a defined surface tension and density whereas your skin and hair on your body might change.  The gravity does not change unless you are in space (so maybe getting dry in space is not such a big deal). 

So how do mammals with hair get dry?  This was the question researchers asked.  And more interesting:  What frequencies are needed for a dog and other animals to shake water from their body?




The conclusion?  In order for a small animal (like a mouse) to get dry it needs to shake faster (30 Hz) whereas an animal like a dog the size of a Labrador (4 Hz) or larger say a Panda bear would need far less shaking in order to get the dermal tissue dry enough.  Loose skin also factors into the equation.  If an animal as small as mouse shakes like a Panda he would not get dry.

via io9

Thursday, 6 December 2012

Crazy DNA Remembers its Shape




Just add water and this DNA hydrogel forms into the letters DNA.  The texture reminds me a little bit of those little toy dinosaurs that you put into the water and they grow into bigger dinosaurs.  But hydrogel is not so much different than the superabsorbant polymer in that both are polymers and a hydrogel can contain up to 99.9% water (much less for the larger dinosaur).  
People are doing a lot of different research on hydrogels and have found many applications including: biosensors, environmentally sensitive smart gels, tissue engineering, contact lenses, drug delivery (put some drugs in a hydrogel that slowly releases them over time), water gel explosives and rectal drug delivery.  Some other less common uses are breast implants and adhesives.  Scientists are trying to get the right physicochemical characteristics like rheology, viscoscity, and surface tension to help make new applications.  
What makes this hydrogel different?  Firstly, it is made using DNA.  DNA  make different shapes during replication and branching.  Understanding  branched DNA has led to making new shapes with  DNA, termed DNA origami.  This new molecular scale engineering have also helped scientists make new drug delivery vehicles e.g. putting drugs in a box constructed by DNA.  This hydrogel is not so different than the DNA origami except that it reacts to make the shapes with water.
This was reported in Nature Nanotechnology.  We'll see if these scientists can take it to the next level to produce better drug delivery vehicles and perhaps better wound treatments with water absorbing hydrogels.  Possibly the art community might also contribute to make interesting shape shifting hydrogels but hopefully not by making DNA dinosaurs.  

Tuesday, 4 December 2012

Icy Business: The Surfactants Behind Hockey Ice





In Helsinki it is really cold.  I believe yesterday was -15 C.  It was snowing, there was ice and now there is more ice.  Kids have their skates and are playing hockey outside.  My colleague mentioned that he made some ice the other day for his complex.  It sounds like a stupid question but I asked anyway.

'How do you make ice?'
'Well you take water and put it out on the surface.  We have a pump out back with a hose.'
'And?'
'And then you wait for it to freeze. Then you add more water and using a sharp tool you level it.'

I have never made ice but likely the ice that is homemade does not look nor feel anything like you would get in an NHL game. Since I have never made ice I take it for granted the great looking ice at the ice skating rinks and hockey arenas.  There is a lot of work to make ice from the ice makers to the zamboni drivers to clean it as well as some surface chemistry that I was not aware.

Canadians are actually some of the best ice makers as they have made the ice at a number of the winter Olympics (and putting a Loony in the center ice for good luck). They have also created products for making better ice surfaces.  Jet Ice is an all Canadian company that was started in 1979 to make specialty paints and surfactants and a system for ice venues (curling, hockey, bobsled, figureskating ect)Their Jet Gloss - degasification system for optimal strong ice.  This liquid surfactant is added to the ice resurfacing water for the last flood of the day. They say it is designed to remove air trapped in the ice phase, this ice dressing provides a brighter, glossier ice surface.  Like any surfactant this will lower the surface tension of water and allow smaller droplets of water to be formed which possibly helps in making a glossier surface.

So with the help of surfactants (and of course better camera and lighting technologies) you can watch hockey at home or at the arena and see everything better.  You can notice the difference if watch a video from pre-1979 hockey.  You will likely see a very dull nearly brown ice surface.  Today you have a bright surface due to the expertise of the surfactants that the Jet Ice team use.  Check this video out the Guy Lafleur game winner from the 1979 Stanley Cup between the Boston Bruins and Montreal Canadiens. 





And compare it to this brawl between the Boston Bruins and Canadiens brawl a couple of years ago.

Wednesday, 28 November 2012

Surface Tension and Maragoni Effect in your Scotch



This Christmas you may go back home and after a dinner you want a Scotch to warm the stomach a little in the cold.  You finish your Scotch and you look down into your glass to observe little patterns.  Did someone spike the turkey?  Probably not.  You are witnessing art from the physical world.  You are witnessing the Maragoni effect. The Maragoni effect due to the difference in surface tension between the alcohol and water. 

 Via Boing Boing explains the art in the bottom of your Scotch glass.  It is called Vanishing Spirits.  Here is a full explanation of the work.
The idea for this project occurred while putting a used Scotch glass into the dishwasher. I noted a film on the bottom of a glass and when I inspected closer, I noted these fine, lacey lines filling the bottom. What I found through some experimentation is that these patterns and images that can be seen are created with the small amount of Single-Malt Scotch left in a glass after most of it has been consumed. It only takes a very thin layer of Scotch to create; the alcohol dries and leaves the sediment in various patterns. It’s a little like snowflakes in that every time the Scotch dries, the glass yields different patterns and results. I have used different colored lights to add 'life' to the bottom of the glass, creating the illusion of landscape, terrestrial or extraterrestrial.
Interestingly, there was a recent article that was published in the Journal of Nature (I think) by Dr. Peter Yunker on the Suppression of the Coffee-Ring Effect by Shape-Dependent Capillary Interactions i.e. how are coffee rings made. I contacted him to see if he could see any obvious connection between the two liquids and the rings / patterns they create. He got back to me and unfortunately could not explain what was happening with the Scotch.



Thursday, 15 November 2012

Why is Surface Tension Needed for the Maker Movement? Part 1/2




I was in the mall and I saw Bre Pettis on the cover of Wired.  Bre is one of those types of people that I love.  They share knowledge in an interesting way for the masses.  He has likely inspired a lot of people to become engineers, scientists, entrepreneurs or have awesome hobbyists.  The cool thing about him is that from this he started Maker Bot. (See him make a copy of Stephen Colbert's head)

Maker Bot is a 3-D printing company.  They are doing what Apple did in the 1980's.  They are taking a idea formerly only done by hobbyists and they are making a finished product for the masses.  They have introduced the  MakerBot Replicator 2 Desktop 3D Printer which is like the Mac.  And the masses will eventually buy once they figure out what to do with them.  They will know too.  I suspect a huge rise in Etsy, Amazon and Ebay items being sold from these 3D printers.  People will build that irreplaceable small plastic part that broke on your dishwasher that some dish washing company will charge you huge amounts for if they even have the part available.  The 3D printer movement is upon us.



The maker movement is among us.  This movement is being touted as the next industrial revolution.  It could potentially bring all those products being produced in China back to the countries where they are actually consumed.  It will change manufacturing and possibly the jobs that we do in the future.  We might be going to a higher movement in  the future which could in fact change governments creating a Venus project landscape.  Perhaps the only limitations are 1) the ideas needed on what to create 2) the materials needed to create them.

The first could be provided with better science, art and medicine education so people could actually have the idea to make a custom built artificial arms like the one used by Luke Skywalker in Star Wars or plastic fish.  Without these types of education to help push creativity there is little point in continuing the maker movement.  We will not need customized things that interest people but rather just continue to produce mass market junk from a central location as they are now.

The second thing that is needed are the materials to create the objects.  These could be of anything from thermoplastic, chocolate, biological materials and metal.  In order to build layer upon layer these materials have to be in the right form in order to neatly build layer upon layer of your new squishy toy dinosaur or plastic fish.  The rheology, viscoscity and surface tension all need to be understood in order to have a printer cartridge that does not get stuck.  Different kinds of thermoplastics are being made all the time.  Potentially there will be even better in the future for printing faster and more robust items.


This is entirely true for the 3D printing technique fused desposition modeling (FDM) Stratasys offers this for building the material out of different kinds of plastic.  Currently, the fundamental limit is the viscosity and surface tension of the molten thermoplastic (like the material LEGO is made of ABS(Acrylonitrile butadiene styrene)).  One of the best ways to explore this limit would be to use the Kibron EZ-Pi Plus.  Then you could make a fish like in the video below out of several different materials depending on if you are in the range.





Okay now I am excited!  Now I want to go make some stuff...........NEED IDEAS!!! 

Tuesday, 13 November 2012

How to Save Yourself from an Bacterial Outbreak?





Cover everything in mucus.  Although that seems completely disgusting researchers at MIT have found that covering things with mucus will help prevent the spread of infection by breaking up biofilms.  You would think intuitively that mucous are the part of the infection as many of those people that are reading this (yes the five people) have had a cold at some point in their lives.  However, as MIT reports the mucus which are large protein chains with lots of sugar molecules the mucus doesn't grab onto foreign particles and trap them.  The bacteria is simply suspended in mucous so it can do less damage. 



The surface tension and other physicochemical properties like rheology, and viscosity may be important characteristic that traps the bacteria .  A typical surface tension of mucus in the a healthy adult may be 50 mN/m and vary by 10 mN/m in a diseased adult.  I suspect that all proteins in the mucous are not equal so potentially some people may trap bacteria in their mucous better than others.  If the surface tension of your mucous changes you might be able to detect diseases.  Secondly, understanding the surface tension of mucus will also help of better delivery of nebulized drugs.  One easy way to measure the surface tension of the your mucus is with the EZ-Pi Plus.  This device might help to pave a new treatments for cancer, lung infections and fighting the common cold.

Monday, 5 November 2012

How to detect urinary problems by peeing?



Unfortunately, this blog post is not for women or men that pee while they are sitting.  At this point I am peeing standing.  It is always amazing to watch the color, flow and protein amount (those bubbles that you see in the morning protein) in my pee.  Call it crazy call it what you will but I think it is important to know your body and what is coming out of it.  I particularly like beet root for example because it makes me look like I am peeing fire like some kind of angry dragon.  Today I stumbled on this interesting headline:

'Men should go with the flow at urinal'

In this news story covered by the  New Zealand Doctor newsroom correlates peeing flow rate and shape characteristics due to the changes in the surface tension of the pee to potentially detect some medical problems.  A computer model of liquid jets escaping different outlets (think of a rubber hose and compressing it to make ovals and other shapes) and then they compared their findings with the volunteers streams.  They could diagnose a number of urinary problems.  There is a interesting relationship between shape and flow rate when peeing 'which suggests poor meatal opening during voiding'.

"This has advantages over existing [urodynamic testing] in that it is completely non-invasive, simple and cheap to implement and avoids inaccuracies associated with voiding in a clinical setting and obtaining data from a single void," the researchers said. So what does mean for you?  Nothing if you pee sitting down.  However if you watch watch while you pee, maybe you could take a video of it and send it to the researchers.

You also do some simple tests by measuring the static and dynamic surface tension of your pee with a surface tensiometer to understand whether you have rheumatic, neurological or oncological diseases as well as other things like jaundice. 

Thursday, 1 November 2012

Row, Row, Row your Leg: The Secret behind Water Strider's Movement in Water




Water striders are an insect people describe as an animal that harnesses the physical properties of surface tension for its mobility.  You would think that after several years of studying water striders an insect no larger than a quarter you would have figured them out.  There is still a lot to learn apparently.  

Nobody really understood how they push forward to move.  People thought that capillary waves were used to move.  A MIT math major and high speed cameras helped to solve the puzzle (loving high speed cameras in science from hummingbirds to water striders they are more useful than ever before).  Hu (MIT math guy) along with his PhD supervisor John Bush found that the water striders only use the middle of their three pairs of legs to "row" across the water.  The ouring leg creates a vortice just underneath the surface that twist away from the standing legs which due to surface tension are luckily on top of the water.  

Wednesday, 31 October 2012

MOF based motorboat

MOF based motorboat 

Basically they structured peptides in a metal organic framework (MOF).  A cage where peptide (small proteins).  When a salt that chelates and degrades the MOF is introduced the peptide leaks out make a hydrophobic aggregate on the surface of the water.  This reduces the surface tension of the water at that point and makes a surface tension gradient propelling the boat forward a phenomenon known as the Maragoni effect (tears in wine).  Cool right?  We have seen similar boats like this before (like that kid in the science fair and Robin Ras at Aalto) where they use some hydrophobic substance to propel the boat.  The peptide aggregation is something interesting mainly because you might be able to use different peptides or perhaps other biochemicals like nucleotides to get a more hydrophobic effect.

Check out the original article from chemistry world.

 
Still cannot help you when you are stranded at sea.

Monday, 22 October 2012

The Hummingbirds Tongue and Capillary Action

The hummingbird (Archilochus colubris) drinking from a transparent feeder; Credit: © Wonjung Kim, Franc¸ois Peaudecerf, Maude W. Baldwin, and John W. M. Bush





If you are drinking from a straw this weekend you may notice that some of the water or whatever you are drinking using a straw rises in the straw more than the water in the glass.   This occurs because the surface tension of the water and its attraction to the straw are stronger than gravity.  The same effect will also occur if you place a sponge in water so the water rises through the different bubbles of the sponge defying gravity.  This movement through a thin tube and through bubbles is called capillary action.

So it is no surprise that plants use this for their root system and animals use it.  Capillary action in hummingbird's tongues was recently found to do the same thing by researchers at MIT :



they use 'an incredible self-assembling capillary siphon. Because nectar is stored in shallow, small scale areas in flowers, the tongue is not under the surface but rather adopts capillary action as its preferred method of taking out the "juice."' (as EarthTimes reports)

This is likely how the small hummingbird has survived.  It has exploited this small niche allowing itself to drink the nectar other birds cannot reach.  Surface tension properties allows the hummingbird to be awesome!


See full article here.





Tuesday, 16 October 2012

Drugs, Acoustics and Surface Tension




With the right music you can change the world.  With the right drugs you can change the world.  With the right drugs and right music you have Motley Crue.

Well.....Actually if you put a certain frequency of sound you move a liquid.  Some people thought how to use this for science and they came up with Labcyte.  Labcyte is a liquid handler that moves liquids not with a traditional pump and pipette robots but with acoustics.  It is innovative because this tool changes liquid handling overall without cross contamination from pipette tips.  It is allowing for drug companies to get better results than traditional handling procedures due to concentration effects.  If they could figure out how to accurately determine the surface tension using acoustics  they might be able to compete with companies that make tensiometers.

However, what is even more interesting than Labcyte and handling drugs is actually making drugs using acoustical waves or crystallizing drugs using inverse acoustics.




Drugs when made can fall into two categories: amorphous or crystalline.  For some reason the crystalline drugs do not get absorbed as well.  Amorphous drugs get absorbed in the body better and in lower quantities.   The Department of Energy in the US has found that using acoustics, drugs can be levitated to make amorphous drugs.  The surface tension of the aqueous solution allows the drug to stay in tact when levitating (like in zero gravity).  Likely, the drugs on the surface of the liquid probably form different hydrogen bonds or other types of bonds with each other to form the amorphous drug than in a crystallized form.  For some reason (not sure why) the membranes in the body like these antigravity amorphous drugs more.


Monday, 15 October 2012

My Surface Energy Reducing Non-Stick Pan: A Salute to Teflon

I love cooking.  Cooking to me is the Jeux de vie.  Lately, I have been learning how to cook French and Italian food.  Both require either butter or a lot of olive oil.    In old times part of the reason people use oil or butter was partly for taste and partly to make the things you are cooking not stick to the pan.  If you are cooking pasta and you do not add oil the hydrophobic parts of the starch will make the pasta stick together.  If you are cooking eggs likely part of the eggs will be stuck to the pan.  This is mostly evident if you are using an old cast iron pan.  People know that you need much more oil in order for the food not to stick to the pan.   The non-stick pan was invented for this purpose.  To make eggs and everything else not stick while requiring the need for less oil and fats.  The non-stick pan also saves a little time and frustration when cooking and cleaning up afterwards. 



Tefal Pots and Pans



Around seventy years ago non-stick pans were not available.  The main part of the non-stick pan did not exist.  At the time there was no thermoplastics (or none that I am aware of) that existed to reduce the surface of energy of pans.  So butter, oil, wax and spam were widely the best way to do this before teflon was invented.  The interesting thing about teflon was it was a nice accident.




This is described in Plunkett's own words:

 'On the morning of April 6, 1938, Jack Rebok, my assistant, selected one of the TFE cylinders that we had been using the previous day and set up the apparatus ready to go. When he opened the valve — to let the TFE gas flow under its own pressure from the cylinder — nothing happened. Jack called me over and asked whether we had used all the TFE from that cylinder. I said, I don't think so. We both tinkered with the valve a bit, and then thinking it might be stuck or closed in some way, we disconnected the cylinder from the line and pushed a wire through the valve opening. Still no TFE came out, although the weight of the cylinder showed that there was material inside. We were in a quandary. I couldn't think of anything else to do under the circumstances, so we unscrewed the valve from the cylinder. By this time it was pretty clear that there wasn't any gas left. I carefully tipped the cylinder upside down, and out came a whitish powder down onto the lab bench. We scraped around some with the wire inside the cylinder — or maybe I tapped it — I don't remember which — to get some more of the powder. What I got out that way certainly didn't, add up, so 1 knew there must be more, inside. Finally, more out of curiosity I suppose than anything else, we decided to cut open the cylinder. When we did, we found more of the powder packed onto the bottom and lower sides of the cylinder.'


 Sometimes a happy accident happens. I called the guys at Dupont one time and they told me a similar story.  It is quite funny but science is sometimes an accident.  Without Fleming leaving his bread out on the table we would not have had penicillin.  However, the people making these ´´discoveries´´ like Plunkett or Fleming need to fulfill to secondary need that it is an actual discovery.  So with Plunkett´s discovery that this white stuff was actually a valuable he could reproduce it in the lab and help to make DuPont billions and billions of dollars.  Dupont would go on to use it for a number of applicatons it thought about.  The material allows water and oil to not absorb due to the low surface energy of teflon and the surface tension of water and oil is too high to stick to the pan.  If one were to put water on a teflon pan you would see a surface energy creates nearly a 180 degree angle between the air-water and surface of the teflon  coated pan.  Put another way the water molecules are more attracted to themselves than to the teflon molecules in the pan. 

Other inventions for a great material come from the public.  Fourteen years after Plunkett´s discovery of teflon a French engineer named Marc Gregoire created the first pan (likely he knew that the French tradition of using a lot of butter for cooking was not healthy).  Actually his wife urged the engineer to use the material he was using on fishing tackle on her cooking pans.  That company called Tefal is still around today.  The first US made Teflon pan had less success as the ´´The Happy Pan´´ (not really sure why a pan should be happy but it is some 1950´s bad marketing gimmick).

So due to a few industrious people by accident and coincidence made teflon pans.  Now I am going to use my Tefal pan to cook some pancakes. 

Saturday, 13 October 2012

Bouncing Water Droplet



Still amazed on what you can do with a high speed camera, water and a needle.  Noah Philips shows that water droplets bounce.  Surface tension is amazing....

Wednesday, 10 October 2012

Sailing Last Summer




I went sailing last summer and was thinking about how to explain the difference in buoyancy to surface tension.  To a person they could seem like similar things.  However, they are not.  For buoyancy there is an upward force on the object from the water.  The boat is buoyant and is maintained floating because of this upward force from the particles on the bottom of the boat.  With surface tension there is only the particles on the surface of the water that affect the thing floating.  Since this has less force mostly small things like paper clips can float on the surface of the water and be maintained solely from the surface tension of the water.  Adding soap this surface tension and the small bonds maintaining the paperclip are broken and the paperclip sinks.  Here is a similar explanation from science blogs.

Friday, 5 October 2012

Wednesday, 3 October 2012

K-Y Jelly- the Lubricant of the Century




K-Y Jelly is an awesome lubricant that is unparalleled by other lubricants.  It is used at hospitals and other practical uses (like making Arnold Schwarzenegger glow in the dark green blood) or wrestling.  One scientific use is to use it as a gonioscopic fluid.  It is like the Duct tape of lubricants.  However, most people use it just for sex.  Johnson & Johnson caught onto this trend and started making this into a  significant brand.  Here are a bunch of commercials that are funny and it all started with a good lubricant that reduced the skin's surface tension....





-Y Jelly was made by Johnson & Johnson.  glycerol BP, propylene glycol BP, hydroxyethyl cellulose,
hydrogen phosphate buffer, and water.  Although it would seem desirable to use natural products like mud, cream corn, Vaseline or other products they are not so good.. One thing that K-Y Jelly does really well is to "surface tension" of the skin without being appreciably absorbed. Vegetable oils do make the skin feel slippery, but do so weakly as compared to glycerin based, (water based) lubricants.  The surface tension of lubricants like K-Y Jelly and ability to reduce the surface tension of the things skin is really important.  

There is a actually a theory called lubrication theory in fluid dynamics which describes the flow of fluids (liquids or gases) in a geometry in which one dimension is significantly smaller than the other.  The interior flow parameter needs to be known and the pressure distribution of volume need to be solved.  In the case of K-Y Jelly on skin however a free film lubrication theory is used.  This theory involves one of the surfaces to be a free surface and the surface tension is a dominant factor in understanding the position of this free surface.  I do not understand the last sentence I just wrote.....and should look up more on this theory.

Anyways, I know that when you use K-Y jelly you will notice that it makes you feel like your skin is more wet and allows a thin film to cover whichever part you are using the K-Y jelly with.  This allows less Van der Waals, hydrogen bonds and less adjoining forces to come in contact with the skin surface.


One excellent instrument to help test the surface tension to make better lubricants would be the EZ-Pi Plus.  It offers both static and dynamic surface tension to help researchers make the best formulations.  This and other instruments are used at 4/5 of the major cosmetic and toiletry companies. 

Monday, 1 October 2012

How Can Scorpions Save Us?




I am not talking about the 80's band the Scorpions with classic hits like:     I am talking about the the little ectotherm canibals, with a nasty stinger that live in the dessert, give people nightmares and occasionally give people a larger sting of a giant hospital bill. 

However, the venom from scorpion bites could be a double edged sword since it could also people against drug resistant bacteria.  Scorpion venom has phospholipase A2 a enzyme protein that destroys fat or lipid molecules and small proteins or peptides that have an antimicrobial effects.  Antimicrobial means that it can destroy microbes e.g. bacteria.  Why is this awesome?  Well these bacteria do not react any sort of antibody so there is little doctors have at their disposal.  Scorpion venom could easily help.  (Likely they could just order the peptide in large quantities) and be very effective to destroy the bacteria as shown in this Wired (July 11th) by Robert Hancock of the University of British Columbia.




In the video this is one way that antimicrobial peptides can penetrate and destroy bacterial cell walls.  There are actually several ways e.g. carpet model, leaky slit model, barrel-stave, or toroidal pore model. 



What does this have to do with surface tension?  The lipid molecules in a bacterial membrane (or normal membrane for that matter) have a tensile strength that prevents substances from getting into the membrane.  Several bacterial membranes have a net positive charge and the antimicrobial peptides can bind and destroy the membrane without 1) any disruption of normal human cells 2) use of antibiotics


There are a nearly infinite number of combinations that can make good antimicrobial peptides.  Several of the best ones are evolved from nature and are listed on this database.  A good way to test them before subjecting the antimicrobial peptides and yourself to deadly bacteria is to use a Delta-Pi or Delta-Pi 4 surface tension device.  Both of these units have helped researchers to understand the penetration and effectiveness of antimicrobial peptide to disrupt the bacterial membrane.


Wednesday, 26 September 2012

Understanding Membrane Biology and Surface Tension with Meringue







I am particularly interested in Molecular Gastronomy.  As a biophysicist and amateur chef I love thinking how each protein is becoming denatured, how there is a change in the hydrophobic properties of pasta, or how the phase properties of chocolate changes in a double boiler.  It is amazing and scientific.  People are still exploring new ways to make and manufacture food.  In fact we do have a lot of interesting things to discover in food properties that we never thought imaginable unless science and experimentation is introduced.  Things like eating new kinds of species (e.g grasshoppers), discovering a new process to make something e.g. space icecream or using a different kind of bacteria or yeast for Kimchi or beer production.   We have a lot of things to discover in food since for me making  



Inside-Out Proteins Bubbles

At some point people (possibly French people I should check in Jen Gardner's book Meringue) started beating egg whites, a pinch of sugar and some vinegar so much that they foamed.  The hydrogen bonds were broken then reformed repeatedly until they made a new kind of structure.  The ovalbumin and lysozyme in egg are normally in a water soluble medium so they have their 'water-loving' part on the outside and their 'water-hating' parts on the inside.  This is also their minimal energy state.

However, when you beat these proteins into submission half the proteins are formed with water and the other half are exposed to air.  A new minimum energy configuration is made where you 'water-hating/hydrophobic' proteins are on the outside and the 'water-loving/hydrophilic' proteins are on the inside.  It is as if you were to blow a soap bubble and one part of the soap is exposed to the water in the middle whereas the other part is exposed to the air.  Meringue is these bubbles with two layers of protein separated by water in the same way as the soap bubbles.  Sugar is also mixed into the egg whites to increase their viscoscity.  Cooking helps remove some of the water so the layers become stiff with the sugar forming the hydrogen bonds both sides of the proteins.  If one were to look at a a cross section of a meringue bubble you would see: air outside, hydrophobic amino acids of outside protein, hydrophilic amino acids, sugar, hydrophilic amino acids of inside protein, hydrophobic amino acids, inside air.




Colloidal Mediums 


So we understood the actual molecules (the proteins) behave but let's look at the bubbles as a whole.
The surface tension in the layers of water molecules on the inner and outer surfaces of membranes, hold the water and protein bubble membranes together to create a foam.  The foams are called colloids.  A colloid consists of a  dispersed phase (protein) and a continuous phase (water).

From a thermodynamic point of view,  all emulsions and food colloids are unstable e.g. the free energy of food is higher in the emulsion or colloidal state than it would be if the food were to separate fully into two (or more) macroscopic regions. For example, a meringue is only in a medium of the proteins and the sugar for a certain period of time before the foam breaks down (baking it makes the colloid more stable).

Once you stop whipping the eggs and leave the foam you will see it separate.  The internal interface area of the system creates the excess free energy of an emulsion.  The excess Gibbs free energy of creating a surface of area, dA, can be written as dG ) γ(dA), where γ is the surface free energy density or the surface tension γ ) ((∂G)/(∂A))T,p.  Mixing other ingredients like sugar, emulsifiers or surfactants can help to change the free energy of the system and potentially stabilize the colloid mixture so it won't separate so you can get the Meringue Pie for whatever occasion!


 





Molecular Gastronomy: A New Emerging Scientific Discipline Peter Barham et. al  (2010) Chem. Rev. 110, 2313–2365

http://boingboing.net/2012/09/04/the-history-and-science-of-mer.html

Wednesday, 19 September 2012

Oil Spills Part III: fluoroPOSS




There is a race to clean up the oil spills.  So many different research groups are covering this.  And the video pretty much explains it all. These researchers from the University of Michigan show that an ordinary polymer and a nanoparticle called fluoroPOSS can help to separate oil.  They make a coated filter and then dipped it into the water mixed with oil.  What happens is some kind of magic.  The nanoparticles (think like putting oil into your teflon pan it is a similar material) have a low surface energy causing the oil droplets to strongly attach to eachother.  The oil droplets for beads on the surface of the filter (which was seen as strange).  The opposite happens to the water.  The capillary action governed by the surface tension is different so oil beads up and the water is washed away.  The best part of the process is that it happens with gravity (so no special machines) and  can reuse the material for 100 hours before getting clogged..

How did the real life tests pan out?  The group has a 99.9 percent efficiency! 

Thursday, 13 September 2012

Cleaning up oil spills with ferric fluids part II



I talked about ferrofluids soaps that was researched at the University of Bristol and how they could be used  for oil spills and the like.  These researchers at MIT tried it out. They used magnets really, really tiny magnets to transform oil like oil polluting the Gulf of Mexico into trapping it with a ferrofluid that can be manipulated.  This could separate the oil from the water then could be recycled and the oil stored.  Simple?  Well it sounds simple but that is why they are still researching it.

[Via MIT and Tim McDonell and the Guardian and Robert T. Gonzalez at Via Io9 ]

Wednesday, 12 September 2012

Why is it 72 dynes?

Really the surface tension of water is 72 dynes?  Yes.  As the name of this blog suggests it is only 72 dynes.  However, according to a study by Angus Gray-Weale and colleagues this could be even larger depending on the attraction between hydroxide dipoles but is reduced by a 'layer of hydroxide-enriched water extends up to a nanometre'.  The results are controversial but interesting as they still try to understand surface tension at different levels.  Still more understanding is needed on both macroscopic and microscopic levels to understand what is happening at the air-water interface.  For a summary of the article it is here:

 
http://www.rsc.org/chemistryworld/2012/08/getting-under-skin-water




References

  1. M Liu, J K. Beattie and A Gray-Weale, J. Phys. Chem. B, 2012, 116, 8981 (DOI: 10.1021/jp211810v)


Monday, 10 September 2012

How to Improve Teaching about Surface Science in Schools?

Two people asked me a couple of questions in the last couple of years that got me thinking about teaching surface chemistry and surface tension better in schools.  After hearing these questions I thought that there could be a lot of improvements........


Question 1:
I was at the Biophysical Society Conference a couple of years ago.  A researcher from Seattle asked me: Why aren't there any monolayer devices in undergrad university labs?

This question surprised me.  I studied biochemistry and never really got into to biophysics until after my undergrad years.  I looked into it further and it seemed that there were not a lot of university teaching laboratories with good monolayer facilities.  Several of the teaching of monolayer happens in academic research labs.  However, several simple systems could be understood in physics, biophysics and surface chemistry laboratories using simple, inexpensive, student proof instruments.

One student proof instrument for measuring films could be the MTX.  I have seen this instrument used and abused by students in our lab.  Even after 7 years it still runs and allows our group to make interesting advances in surface science.



2) Question 2:

This was asked by colleague after saying, 'in Spain we had this really really ancient Du Nuöy ring that was all bent and we had to teach a lab with this.  The surface tension of water would come up to be 52 dynes/cm2.  I was the teacher.  Then a student asked me, 'but isn't it supposed to be 72 dynes/cm2'.  In which I replied while sweating, 'Yeah well somethings wrong with the instrument'. 

This has likely happened to many teaching assistants and professors in trying to demonstrate how to measure the surface tension of water or some other liquid.  It is a pain to actually teach using devices that are destroyed, difficult to use and difficult to calibrate.  So teachers forgo teaching about interesting fun systems like beer foam, the films covering devices like the iphone, why certain body soaps (eg. Axe vs. L'Oreal ) are better.



One student proof instrument for teaching surface tension in a lab is the AquaPi.  I have heard  from the Aalto University's chemistry teaching lab that the instrument is fast and reliable.  The students can understand surface chemistry instead of trying to make difficult measurements.

Overall buying a studentproof instrument makes everybody's lives easier!




Friday, 7 September 2012

Spiderman Sticking to a Submarine: New Bionic Material Even Sticks To Surfaces Underwater

New Bionic Material Even Sticks To Surfaces Underwater

I was always wondering how Spiderman could climb walls and whether his webbing could work underneath the water say if he was to stick to a submarine or something.  Bugs as you know can crawl everywhere.  I found some insects upside down on my plants and I wondered: 'How did they get there?'  Well surface tension is at play (also insects have a weight strength distribution that is beyond our imagination just look at Antman).  Insects use capillary forces with oil-covered adhesive called setae.  But what happens when the it rains and the properties of the surface of the plant change.

Well scientists Gorb and Honosa published: 'Underwater locomotion in a terrestrial beetle: combination of surface de-wetting and capillary forces', Proceedings of the Royal Society B to describe this.  The terrestrial leaf beetle. The cool thing about the leaf beetle is it uses air bubbles trapped between their adhesive setae producing a boundary between the air, the liquid and the solid which ultimately produces capillary adhesion under water.  One necessary requirement would be for the surface of the leaf but as you know many leaves (including the lotus) have hydrophobic property.

But what is this solid material (the Spiderman webbing) for the beetle.  The solution was a micro structure they designed which is an 'artificial silicone polymer structure with underwater adhesive properties'..  One could think of any field of application for underwater technologies like optics or perhaps even allowing Spiderman to stick to a submarine better.

Citation: Naoe Hosoda and Stanislav N. Gorb, 'Underwater locomotion in a terrestrial beetle: combination of surface de-wetting and capillary forces', Proceedings of the Royal Society B, Published online before print August 8, 2012, doi: 10.1098/rspb.2012.1297

Spiderman Sticking to a Submarine: New Bionic Material Even Sticks To Surfaces Underwater

New Bionic Material Even Sticks To Surfaces Underwater

I was always wondering how Spiderman could climb walls and whether his webbing could work underneath the water say if he was to stick to a submarine or something.  Bugs as you know can crawl everywhere.  I found some insects upside down on my plants and I wondered: 'How did they get there?'  Well surface tension is at play (also insects have a weight strength distribution that is beyond our imagination just look at Antman).  Insects use capillary forces with oil-covered adhesive called setae.  But what happens when the it rains and the properties of the surface of the plant change.

Well scientists Gorb and Honosa published: 'Underwater locomotion in a terrestrial beetle: combination of surface de-wetting and capillary forces', Proceedings of the Royal Society B to describe this.  The terrestrial leaf beetle.





The cool thing about the leaf beetle is it uses air bubbles trapped between their adhesive setae producing a boundary between the air, the liquid and the solid which ultimately produces capillary adhesion under water.  One necessary requirement would be for the surface of the leaf but as you know many leaves (including the lotus) have hydrophobic property.

But what is this solid material (the Spiderman webbing) for the beetle.  The solution was a micro structure they designed which is an 'artificial silicone polymer structure with underwater adhesive properties'..  One could think of any field of application for underwater technologies like optics or perhaps even allowing Spiderman to stick to a submarine better.

Citation: Naoe Hosoda and Stanislav N. Gorb, 'Underwater locomotion in a terrestrial beetle: combination of surface de-wetting and capillary forces', Proceedings of the Royal Society B, Published online before print August 8, 2012, doi: 10.1098/rspb.2012.1297

Monday, 3 September 2012

Breaking Bad Crazy Blue Meth

I am a huge fan of the series Breaking Bad (some spoilers).   I love the Brian Cranston's acting as well as the other characters in the show.  The main characters tragic demise into a world of making crystal meth is astonishing from the first show until the fifth season.  Besides the characters and the plot, I also love the science.  There are several science scenes that would put McGuiver to shame since they help the bad guys (Mr. White and Jesse) get out of situations from making a rudimentary battery, making ricin from beans, building a powerful electromagnet to making better quality methamphetamine. 

Although I do not condone making illicit drugs, the process behind making them and the effects of these drugs is quite interesting..One scene in the episode where Jesse and Mr. White are making meth under the tent in the house that is being fumigated (in Hazard Pay).  It was a beautiful scene where the reactions happening are visualized with sparks and you can see the flow of the reaction.  It makes me want to do more chemistry.



Artists illustration of what chemical reactions look like.  Probably just ink in water.


 It got me thinking of what the surface tension of this blue meth is and how it can help to make better drugs. The surface tension does help in forming the crystalline solids. Crystalline solids are formed by cooling and solidification from the molten (or liquid) state. If you made chocolate this property can be seen easily when the chocolate cools it forms small cocoa butter crystals on the surface after you cook a molten chocolate. This is a first order phase transition. The crystal and melt have an interfacial discontinuity due to a surface tension with a positive surface energy. A metastable parent phase is stable with respect to the nucleation of small embryos or droplets from a daughter phase if their is a positive surface tension. Positive surface tension in this case means the surface of the meth between that of the molten liquid. The surface tension is not a property of the liquid alone but a property of the liquid's interface with another medium. Also the walls of the containers are part of this interface. Where the three surfaces meet (the container wall, the molten meth and the surface) gives a certain contact angle which is the angle the tangent of the surface makes with the solid surface. This surface tension between the liquid-solid surface needs to be positive in order to make crystals.

If one were to make any kind of crystals of a pure substance you would see crystals form at this boundary between the container wall, molten liquid the liquid surface. In you have a smooth surface you can always take a glass stirring rod and scratch this surface. This would allow you to start the nucleation process. Perfect crystals as in Walter White's blue meth would likely grow exceeding slowly. Unlike, Jesse's chilipepper meth (in the first season) he does not add any impurities to the process.  This allows Jesse and Walter to make Heisenberg's Blue stuff.  

Psychonaught Wikicommons



(Surface tension described here would also be good for crystallizing proteins in a better way.  In fact protein crystallographers can use surface tension devices to make better looking crystals).


Monday, 13 August 2012

How to Make Plastic Planes to Graphene Rockets?


This is what I picture a graphene rocket to look like.


I was listening to Bill Nye on the Nerdist podcast this morning.  Bill Nye is awesome and one of several reasons I decided to go into science (and also for potential superhero/supervillain capabilities).  Telling science to the everyday man and exploring new frontiers is something I like to do and something I learned from Bill Nye's shows.

One thing that I did not know about Bill Nye is that he worked for Boeing and he was fairly passionate about talking about making better spaceships.  On the Nerdist Podcast he mentioned that an airplane like a Boeing 747 is about 30% fuel whereas a rocket is about 70% fuel.  That is a lot of fuel to be sending to people and things to space.  So every extra kilo of baggage the astronauts take costs a lot of fuel (so you cannot take your favorite pillow to space).

To save on fuel you would need to get rid of extra weight for things that you cannot get rid.  This can be done with ipads to save paper weight of the navigation charts, better designed seats, and lighter people. 

It was interesting listening to Bill Nye talk about the space and his work with the The Planetary Society.  He talked  about plastic planes or carbon fiber planes that they are making at Boeing.  Eventually someone like techies Elon Musk at Tesla and Space-X or former Microsoft Paul Allen will make a plane or a rocket but instead of steal make it out of plastic.  In fact Paul Allen and a company called Stratolaunch are already in development of this plane and booster rockets will be made by Space-X.  Seriously, check out the story here.   I am all for the post Howard Hugh's era of making private aeronautics research and development.  More billionaires need to take the helm and take to the skies. 

But is plastic the best material?  Should we  do people trust plastic?  Advances in plastic have been huge since Dustin Hoffman was introduced to plastics in 'The Graduate' Can it withstand space? 
Are there better materials to go to space?  I thought of graphene.

Graph what?  Graphene is a new material being researched that has all the properties to make a great rocket ship.  It is strong, light and thin.   How strong, how light and how thin?
http://www.getbig.com/boards/index.php?topic=408535.0

For example as quoted directly:

“It would take an elephant, balanced on a pencil to break through a sheet of graphene the thickness of cling film.” said Columbia University Engineering Professor James Hone; continuing, "Our research establishes graphene as the strongest material ever measured, some 200 times stronger than structural steel." (emphasis added) Source: Scientific American online

A graphene sheet is only one atom thick, so it takes 3 million sheets on top of each other to be the thickness of one millimeter!
It is so strong because it is made of Carbon atoms double-bonded together in a lattice. “It would take an elephant, balanced on a pencil to break through a sheet of graphene the thickness of cling film.” said Columbia University Engineering Professor James Hone; continuing, "Our research establishes graphene as the strongest material ever measured, some 200 times stronger than structural steel."
(emphasis added) Source: Scientific American online

A graphene sheet is only one atom thick, so it takes 3 million sheets on top of each other to be the thickness of one millimeter!  It is so strong because it is made of Carbon atoms double-bonded together in a lattice.  



Graphene would be an excellent material to be used for a rocketship of the future.  It is unbelievably light.  It is unbelievably thin and it is unbelievably strong.  

However, the future is can be far away depending on how fast the research can be conducted, and whether it can be mass produced.  A couple of years ago I went to a conference and learned that they were making repoducable sheets of graphene using In order to make these lattices you need to use graphene on interfaces.  A really cool method made by researchers at Northwestern University in Illinois made for several applications using Langmuir Blodgett monolayers.  Another paper using the same technique can be found here.

A group in Sydney has recently made graphene paper.  This is 10 times stronger than carbon fiber. 

The LB monolayers  simple device allows the graphene to be one molecule thick then made into a lattice of molecules.  These simple devices starting from a kitchen sink of a housewife in England will help us make the best rockets to thrust us into space.  Hopefully, the research in this area will be successful and we will get to the moon, to mars or beyond....

Wednesday, 1 August 2012

'Don't be Splashy' Olympic Syncronized Diving

I was watching Olympic synchronized diving and was cheering on the Canadians.  The men's and women's teams both won metals.  It was my first time waching this competition and was suprised that they really judge splashiness.  One way to stop splashiness is to change the posture of the divers by using rocktape to help them streamline into the water.  What causes the splashyness?

The antithesis to divers are bellyfloppers.  Everybody has probably belly flopped at some point (not everybody is an Olympic diver).  So what is belly flopping and how does water's properties play into making splashes?

Two factors play here: the compressive strength and the shear strength. The compressive strength (and oppositely the tensile strength which is related to the surface tension) of a material like water depends on the molecules. The shape of water molecules determines how they line up (or don’t line up) when under pressure and compressed to move closer together. Atoms in a body of water will try to find an equilibrium position and distance themselves throughout the material (in this case the ocean) to return to equilibrium. The compression strength is what makes the belly flop hurt and makes me cringe. Compressive strength is measured in dynes/cm2.

The shear strength is like the shearing force or rigidity. Shear strength is measured in dynes/cm2. Water has zero rigidity. Like if you were to turning a round jar of water with a fish in it--the jar turns but the water does not, and the fish is still facing the same direction. This is because the sides of the jar slide across the water without affecting it--water has no shear strength. Put gelatin in the jar and you have a material with shear strength--and the fish will turn with the jar (do not try this at home). In the case of the belly flopper, since he jumped with his whole body parallel to the plane of the water he confronted the in-compressibility of water mentioned above.

However, during training the Canadians and other divers are likely to suffer severe injuries if they attempt a new dive and spin out of control.  One example is the German diver Stephan Feck who during his 3 meter spring board dive hit the surface of the water with his back after failing a pike.  See horrific video here.


What the Feck?




At several points during the evolution of the sport people created better tools to make the once named fancy diving safer and more fun.  A tool called the bubble machine invented by Herb Flewwellyn (a Canadian) in the late 1960's makes diving a little safer.  It works by creating a mass of bubbles in the center of the diving well.  The bubbles break the surface tension of water to create a "softer landing zone" .  The compressibility of the water would still be a factor but the initial hitting of the water may relieve some of the energy needed to break the water.


So the next time you dive in water you put your hands in front to break the water as the Olympic swimmers do, and, if you do it right, you slide right into the water without pain--again because water has no shear strength. You also displace as little water as possible making less of a splash. Diving like this would make me cringe less.

(Some info was found here in this great explanation of seismic waves).