A material that is as light as plastic yet stronger than steel and 4–6 times harder to damage than bulletproof glass could soon be used to protect smartphone screens. The substance created by experts from Massachussets Institute of Technology achieves something long thought impossible -- polymerisation in two dimensions. Polymerisation is a process by which small atoms called monomers are joined together, usually to form long, spaghetti-like chains called polymers. These can then be shaped into three-dimensional objects such as water bottles, by means of injection moulding. The researchers, however, have succeeded in creating a material that self-assembles instead into two-dimensional sheets that are more like lasagne than spaghetti.
A guest post by Somesh Mohapatra, Rafael Gómez-Bombarelli of MIT IntroductionA polymer is a material made up of long repeating chains of molecules, like plastic or rubber. Polymers are made up of subunits (monomers) that are chemically bound to one another. The chemical composition and arrangement of monomers dictate the properties of the polymer.
MIT researchers have developed a new material that's as strong as steel but as light as plastic. It can be easily manufactured in large quantities, and the use cases range from lightweight coatings for cars and phones to building blocks for massive structures such as bridges, according to Michael Strano, the Carbon P. Dubbs Professor of Chemical Engineering at MIT and the senior author of a new study. "We don't usually think of plastics as being something that you could use to support a building, but with this material, you can enable new things," he said in a statement from MIT. "It has very unusual properties and we're very excited about that." The material is several times stronger than bulletproof glass, and the amount of force needed to break it is twice that of steel, despite the fact that the material has only about one-sixth the density of steel, according to MIT. The researchers were able to do this by developing a new process to form polymers.
Ink containing polymers that can store data has been used to write a letter containing a hidden message – the encryption key to unlock a text file of L. Frank Baum's The Wonderful Wizard of Oz. Eric Anslyn at the University of Texas at Austin and his colleagues have developed a technique that involves steganography – the practice of hiding one message inside another. The team generated a 256-character cipher key to encrypt and decrypt files using the Advanced Encryption Standard (AES), a common cryptography method. "Because they're a polymer with a very specific sequence, the units along that sequence can carry a sequence of information, just like any sentence carries information in the sequence of letters," says Anslyn. Each polymer was made up of 10 smaller compounds called monomers.
The development of chemically recyclable polymers offers a solution to the end-of-use issue of polymeric materials and provides a closed-loop approach toward a circular materials economy. However, polymers that can be easily and selectively depolymerized back to monomers typically require low-temperature polymerization methods and also lack physical properties and mechanical strengths required for practical uses. We introduce a polymer system based on γ-butyrolactone (GBL) with a trans-ring fusion at the α and β positions. Such trans-ring fusion renders the commonly considered as nonpolymerizable GBL ring readily polymerizable at room temperature under solvent-free conditions to yield a high–molecular weight polymer. The polymer has enhanced thermostability and can be repeatedly and quantitatively recycled back to its monomer by thermolysis or chemolysis.