Polyhydroxyethylmethacrylate

Polyhydroxyethylmethacrylate

Poly(2-hydroxyethyl methacrylate) (pHEMA) is a polymer that forms a hydrogel in water. It was invented by Drahoslav Lim 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.cite book | last = Ratner | first = Buddy D. | title = Biomaterials Science, An Introduction to Materials in Medicine | publisher = Elsevier Academic Press | year = 2004 | id = ISBN 0-12-582463-7] These copolymer hydrogel lenses are often suffixed "-filcon", such as Methafilcon, which is a copolymer of hydroxyethyl methacrylate and methyl methacrylate.

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  • Drahoslav Lím — (born September 30, 1925 in Czechoslovakia; died August 22, 2003 in San Diego, California)[1] was a Czech chemist. He invented polyhydroxyethylmethacrylate, the synthetic material used for contact lenses (hydrogel). Lím worked[2][3][4][5] as a… …   Wikipedia

  • (Hydroxyethyl)methacrylate — Hydroxyethylmethacrylate or HEMA is the monomer that is used to make the polymer PolyHydroxyethylmethacrylate. The polymer is hydrophilic; therefore, when the polymer is subjected to water it will swell. Depending on the physical and chemical… …   Wikipedia

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