Newly developed at the Vienna University of Technology, and supremely awesome: Highly tuned mirrors increase the speed and accuracy of 3D printing in nano scale, accomplished through two-photon lithography. But how? Precision lasers are guided through a specialty liquid resin to form the lines and layers that comprise the final object. When the resin simultaneously absorbs two photons, which occurs only at the high intensity center of the laser, the monomers of the resin polymerize and solidify. 

Someone get me a walkman and some language learning tapes, I’m going to Vienna! 

I’m basically thrilled about these rain coats from TERRA; fashion and function?! Prove it. TERRA’s outerwear is designed for urbanites and bikers to go about their business not looking like drowned rats, a significant feat to be sure. The designs are total win, so on to the science.

The most consistent points of failure in water proof outerwear are the seams, while a fabric could be completely impervious, every stitch is a punctured hole and a breach in the system. TERRA wisely solves this issue with thermal bonding, utilizing the melting and reforming properties of thermoplastic Polyurethane.

Thermoplastic polymers are the ones that melt, unlike thermoset polymers, which just burn. (We can have a longer discussion about thermoplasticity in the future, promise)

Polyurethane is a incredibly versatile polymer: adhesives, paint, elastomers, and more. what!? true.  Defined by the presence of urethane linkage, polyurethanes can be variant in their composition, and higly complex. In my opinion the finest example of this is the usage in block co-polymers, combining the highly crystalline sections with softer rubbery sections. 

In some publications (but not on their website) there is claim of biodegradability, I was completely befuddled by this, so I called up the fine folks at TERRA. Speaking with them I learned that the supplier they purchase the Polyurethane from claims that the polyurethane textile is biodegradable.  TERRA is planning to have independent ecological testing of the product undertaken in the near future, and only then advertise the confirmed results. 

In other Polyurethane news, there are two interesting developments. 1) bio-absorable for implantation and cell growth scaffolding.  2) Natural, made from plant oil based glycerol. (I vote this for the next TERRA line. Fancy!)

Now you know what to buy yourself after you return all those gifts. TERRA. 

I recently made a shelf. (no, no images, it’s not up to the demands of my perfectionist tendencies, and I will not have your opinion of me lowered by substandard carpentry.) Back to the shelf. Due to the mediocrity of my fastening system, I needed to fill some gaps, Wood Putty to the rescue! The next morning I realized, what is that crap made of?

ooooohhhh. Acrylic. But what kind of polymer is that? Well, lots of kinds. Could be thermoplastic, could be thermoset; acrylic acid, or methacrylic acid. Options. The defining feature is that it is a resin (vague) and that its polymerization is precipitated by the application of heat and a initiator to the monomer (really vague). But… don’t worry there is a more specific answer to my query. 

It ends up that most acrylic in paint is Poly(methyl methacrylate) or PMMA. This is the clear glass-like plastic seen in products like Lucite® and Plexiglas®. Once dried it gives that hard solid finish desirable in paints, or wood fillers. Interestingly PMMA is hydrophobic and hence water insoluble. (But the package says cleans with water!?) In this case a co-polymer is used, to suspend the PMMA in water, poly(vinyl alcohol-co-vinyl acetate. Just like lipids this polymer has hydrophobic and hydrophilic groups; in-order to satisfy both halves of its “personality” the vinyl co-polymer loops into a circle with the phobic acetate groups facing in and the phillic alcohol groups facing out. This shape leaves a nice dry center for the PMMA to hide from the water in. It is by this means that insoluble groups are suspended in water based materials. This wrapping of a molecule by a second molecule, for the goal of suspension, is termed a latex; hence latex paints. (Latex fun fact by the fine folks at the Macrogalleria)

Cellulose is a fabulous naturally occurring polymer (cotton, wood, hemp etc.) and the base of most early plastics. 

For example: Celluloid, first created in the mid 1800’s as a substitute for ivory in billiard balls. And Nitrocellulose, used in everything from explosives, to film, to the fancy nail wraps I’m sporting right now. 

Once upon a time I went to some polymer group’s dinner and heard a fantastic talk from a professor at Georgia Tech about co-block polymers and self assembly. So here is why this beautiful green stuff above is even possible to make. In a vast oversimplification… Co-block polymers can make highly specified shapes/structures determined on the % of each in the mix. (and their chemical composition, duh) The polymers like to be near themselves, rather than the other type of polymer, which prevents full blending. But what is really fascinating is that rather than make a increasingly thin layer on one edge, minimizing the interface, the polymer with the lower % concentration will disperse itself evenly throughout the other polymer. Meaning that fairly regular and patterned structures will self assemble! Magic! 

freshphotons:

“This electron micrograph (1100 nm wide) shows hollow nanostructures fabricated using a combination of block copolymer self-assembly and sequential infiltration synthesis. Gas phase precursors penetrate the polymer film and selectively grow inorganic material at the interfaces between the two polymer blocks. These novel materials are potentially useful as masks for nanolithography or as nanoscale catalytic reaction vessels.”

Why does everyone have the same great idea at the same time?! Seriously, polycarbonate resin and nitrocellulose. (If someone else published on my thesis work I can’t even contemplate what I’d do. Thank goodness its basic not applied, ha!)

In 1953, polycarbonate resin was invented twice. It was first created in Germany by Dr. Hermann Schnell of Bayer, and then, just one week later in the United States, Dr. Daniel Fox of General Electric announced his discovery. Both companies applied for a patent for the gooey substance, which hardened into a nearly unbreakable solid. Both companies agreed that whichever received the patent would pay a royalty to the other, which allowed Bayer and GE to each develop and market products based on the resin.

Baby’s first experiment! The look on this kid’s face is perfect, he knows how to take the experimental method seriously.

foolonyou:

Fun with superabsorbent polymers. Originally created for agricultural purposes, they now show up in diapers and the material used to mop up oil spills. Oh, and in children’s grow-in-water toys.

Remember Indiana Jones and The Temple of Doom? Remember the snake pit? Good. You’re half way to understanding a fancy polymer chemistry concept.

Polymers are what we like to call Macromolecules, meaning simply that they are really big. To compare: if a water molecule were the size of a nickel, a polyethylene molecule would be 1/4 of a mile long. Back to Indiana Jones, so it’s a nice warm day in the snake pit and the snakes are wiggling happily to and fro, over and under, in a giant swirly spaghetti blob. Now you decide to drive your Land Rover (so British) through this snake room, and what do the snakes do? They slither out of the way, minimal dead snakes, maximum driving efficiency. Now what about a cold day in Egypt? (un-likely but necessary for this example) The snakes are moving very little now, stacked and entangled with each other. Here comes the Land Rover again, and things get messy this time around. (A shout out to Macrogalleria for this metaphor)

This is the exact (ish) way that polymers function, just think of all those snakes as long molecular chains. When they get cold, below their Glass Transition Temperature (Tg), they will break. Ever left a plastic bucket outside overnight in winter? Enough said. Ever put a rubber ball into liquid nitrogen? Do it. 

Glass transition isn’t just for breaking stuff, it’s also very useful for imparting desirable properties to the polymer products in everyday life. A rubber band is only functional when flexible, and above its Tg. While those clear plastic wine glasses, the ones that always break, are below their Tg. The many states of semi-crytaline polymers, bringing variety and functionality to plastics all around you.