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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Photo- and Thermoinduced Sol-Gel Transitions in Blends of Azobenzene Copolymers and Pluronic Surfactants

Deshmukh, Smeet, Bromberg, Lev, Hatton, T. Alan 01 1900 (has links)
Novel self-assembling copolymers of 4-Methacryloyloxyazobenzene and NN-dimethylacrylamide (MOAB-DMA) exhibiting a pronounced photoviscosity effects in water are described. An optimum polymer architecture corresponding to maximum contents of the azobenzene moieties that allowed for the aqueous solubility of the MOAB-DMA copolymer at ambient temperature was observed at a molar fraction of the MOAB moieties in the copolymer of 0.2. When blended with Pluronic F127 copolymers, the MOAB-DMA solutions become both irradiation- and temperature-sensitive and capable of sol-gel transitions depending on the MOAB-DMA content. Effect of the MOAB-DMA copolymer addition to concentrated Pluronic F127 solutions was studied by controlled stress rheology. The presence of the amphiphilic MOAB-DMA copolymers in the micellar Pluronic solutions enabled irradiation-dependent shifts in gelation temperature, while the viscoelastic gel modulus was not significantly affected by the MOAB-DMA copolymers, indicating that cubic lattice of the Pluronic responsible for the gel formation was not compromised. The UV- and T-dependent gelling media might prove to become viable electrophoretic separation matrices. / Singapore-MIT Alliance (SMA)

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