Organic chemistry
Since the invention of the first synthetic polymer product, bakelite, synthetic polymer products have frequently been invented.
Janus particles
This method uses the well-studied methods of producing block copolymers with well-defined geometries and compositions across a large variety of substrates. Synthesis of Janus particles by self-assembly via block copolymers was first described in 2001 by Erhardt "et al." They produced a triblock polymer from polymethylacrylate, polystyrene and low-molecular-weight polybutadiene. The polystyrene and polymethylacrylate formed alternating layers in between which polybutadiene sat in nanosized spheres. The blocks were then cross-linked and dissolved in THF, and after several washing steps, yielded spherical Janus particles with polystyrene on one face and polymethylacrylate on the other, with a polybutadiene core. The production of Janus spheres, cylinders, sheets, and ribbons is possible using this method by adjusting the molecular weights of the blocks in the initial polymer and also the degree of cross-linking.