Artificial latex movies are broadly used throughout many fields, however they normally comprise dangerous components to reinforce their energy. In a current examine, researchers from Japan have developed a brand new class of latex movies composed of rotaxane-crosslinked acrylic nanoparticles. These movies exhibit outstanding mechanical properties, together with glorious crack-propagation resistance with none components, and are simply recyclable, paving the way in which for extra environmentally pleasant supplies.
Artificial polymer supplies, akin to plastics and rubbers, have develop into ubiquitous in our every day lives. It’s, due to this fact, important to make sure that they’re protected, sturdy, and sustainable. That is very true for artificial latex movies, that are broadly utilized in packaging, biomedicine, and electronics.
However what precisely are artificial latex movies? Merely put, they’re a sort of nanoparticle-based movies which can be produced by drying out a mix of polymer nanoparticles and water. Because the solvent evaporates, the nanoparticles develop into extra packed till lastly the interactions between polymer chains on the boundaries of nanoparticles create a coherent movie. Sadly, the latex movies produced this manner are weak. Normally, natural solvents and fillers should be added to the preliminary combination to enhance the mechanical properties of the ultimate product. These components are usually not solely costly but in addition dangerous to the atmosphere.
Fortuitously, a crew of researchers from Japan, led by Affiliate Professor Daisuke Suzuki from Shinshu College, lately developed an modern option to produce robust and crack-resistant elastic nanoparticle-based latex movies with out utilizing such components. Their work, made out there on-line on 16 June 2023 and revealed in Quantity 39, Situation 26 of the Langmuir journal on 4 July 2023, included contributions from Yuma Sasaki from Shinshu College and Professor Toshikazu Takata from Hiroshima College.
The important thing to their method was a novel molecular construction often known as rotaxane, which includes two foremost parts — a ring-like molecule and a linear “axle” molecule. The ring-like molecule is threaded via the axle molecule, which turns into mechanically trapped thereafter owing to the form of the axle terminations.
The researchers leveraged this interlocking mechanism in rotaxane by making the ring-like molecule chemically bind to at least one polymer chain and the axle molecule to a different chain. Subsequent, they ready mixtures of water and polymer nanoparticles via commonplace ultrasonication and subsequent polymerization that, in flip, had been used to supply latex movies. The stretching experiments carried out on these movies revealed that the rotaxane-based technique resulted in some outstanding properties. “In distinction to standard nanoparticle-based elastic polymers, the latex movies composed of the rotaxane-crosslinked nanoparticles exhibited uncommon crack propagation conduct,” explains Dr. Suzuki. “The route of crack propagation modified from being parallel to the crack to at least one perpendicular to the crack, leading to an elevated tear resistance.“
The brand new method to creating latex movies provides many benefits over standard strategies. Most significantly, no poisonous components are wanted to realize cheap movie toughness. Furthermore, since solely a tiny quantity of rotaxane is required, the whole weight of the movies could be stored low whereas preserving flexibility. The proposed latex movies are sustainable as properly. “They’re degradable and could be simply disassembled into particular person nanoparticles by merely soaking them in an environmentally pleasant natural solvent, akin to an aqueous ethanol answer,” highlights Dr. Suzuki. “These nanoparticles can then kind a movie once more upon evaporation of the answer. The findings of this analysis can thus assist create extremely sturdy and recyclable supplies.“
General, the crew expects their work to broaden the scope for the design of recent polymer movies with out components. Such supplies may thus be made biocompatible, with potential functions in biotechnology and drugs along with packaging, industrial coatings, and adhesives.