Hydrophobic hydrogels

Colon LA, Guo Y, and Fermier A. Fritless packed columns for capillary electrochromatography Separation of uncharged compounds on hydrophobic hydrogels. Anal. Chem. 1996 68 2153-2151. 

We have previously reported the design of mixed hydrophilic/hydrophobic hydrogels containing PHEMA and polysaccharide segments, in which the polysaccharide structure is a hydrosoluble hemicellulose with a comparatively low molecular weight obtained from spruce chips by a steam explosion technique and fractionated by size exclusion chromatography (SEC) (1), In this paper we summarize earlier work and add some new results concerning controllability. 

Table 2. Four parameter model for the hydrophobic hydrogels...

Mechanical properties of a hydrogel lens also are affected by the use of a hydrophobic monomer, such as a low alkyl methacrylate. This is particularly important when the water content of the hydrogel lens is very high. The use of these methacrylates helps preserve the required mechanical strength. Methyl methacrylate [80-62-6] (MMA) (I2I), isobutyl methacrylate [97-86-9] (122), and / -pentyl methacrylate [2849-98-1] (123) all have been used for this purpose. 

Because of the many choices of hydrophilic monomers, cross-linkers, and hydrophobic monomers, a large number of formulations have been developed and manufactured into hydrogel lenses. The water content of these hydrogel lenses ranges from about 38%, for HEMA-based lenses, to 80%, for poly(vinyl alcohol) and partially hydrolysed acrylonitrile lenses. Table 2 gives a representative Hst of FDA approved hydrogel materials available to the consumer in the early 1990s. 

As a polycation, chitosan spontaneously forms macromolecular complexes upon reaction with anionic polyelectrolytes. These complexes are generally water-insoluble and form hydrogels [90,91]. A variety of polyelectrolytes can be obtained by changing the chemical structure of component polymers, such as molecular weight, flexibility, fimctional group structure, charge density, hydrophilicity and hydrophobicity, stereoregularity, and compatibility, as... 

The hydrophilic/hydrophobic SIN composition of PDMS with poly(HEMA) and poly(AAC) were proposed as a potential apphcation for high-permeability soft contact lenses. Other sUicone-containing IPNs for contact lenses include polymerization of MMA in the presence of polymerized methacryloxypropyl trimethoxysilane, the cross-linking of a polymeric hydrogel of a copolymer of NVP during the final compression or injection-moulding process. 

Rajagopal K, Ozbas B, Pochan DJ et al (2006) Probing the importance of lateral hydrophobic association in self-assembling peptide hydrogelators. Eur Biophys J Biophys Lett 35 162-169... 

Table 2 Nonionic, Hydrophobic Monomers Used for Hydrogel Synthesis... 

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