Hydrogels and methods for their production
US6559223B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 22, 2001 |
| Grant date | May 6, 2003 |
| Priority date | — |
| Expiry date | Feb 22, 2021 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S525/936
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
Forming graft copolymers in water using labeling of water soluble polymers with photoinitiators. Water soluble polymers can form environmentally responsive hydrophobically stimulated cages. The cages, which contain initiating radicals after irradiation, may be “opened” or “closed” by changes in environmental conditions. When the cage is closed, the radicals are trapped inside and thus do not cause substantial polymerization of water soluble monomers in the same solution. When the cage is closed, the radicals escape and cause polymerization. In another variation, hydrogels and graft copolymers are formed by covalently linking phototoinitiator groups to water soluble polymers that do not form cages. Thus, monomers may form grafts to the polymer, allowing formation of physical hydrogels. The physical hydrogels formed in either case show properties responsive to pH, salt and/or solvent composition, so that the hydrogels may be rendered to a powder by addition of non-solvents and these powders can reform the gels.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.