Poly (pHEMA) is a polymer that forms a hydrogel in water. It was invented by Drahoslav Lim

Drahoslav Lím

Drahoslav Lím was a Czech chemist. He invented polyhydroxyethylmethacrylate, the synthetic material used for contact lenses ....

 for use in soft contact lenses. Copolymers of pHEMA are still widely used today.

pHEMA functions as a hydrogel by rotating around its central carbon. In air, the non-polar methyl side turns outward, making the material brittle and easy to grind into the correct lens shape. In water, the polar hydroxyethyl side turns outward and the material becomes flexible. Pure pHEMA yields lenses that are too thick for sufficient oxygen to diffuse through, so all contact lenses that are pHEMA based are manufactured with copolymers that make the gel thinner and increase its water of hydration. These copolymer hydrogel lenses are often suffixed "-filcon", such as Methafilcon, which is a copolymer of hydroxyethyl methacrylate and methyl methacrylate

Methyl methacrylate

Methyl methacrylate is an organic compound with the formula CH2=CCOOCH3. This colourless liquid, the methyl ester of methacrylic acid is a monomer produced on a large scale for the production of poly .-Production:...

.