Mobility Measurement and Computer Simulation at Specific Sites in Polystyrene Solutions and Gels
Abstract
Trans-- > cis photoisomerization of azobenzene chromophore labeled at the chain center, the chain end, or as a side chain of polystyrene as well as free probe was studied to investigate the mobility at specific chain sites in polymer solutions and gels. The site dependency of the chain mobility indicated that the chain center was least affected by increasing concentration, followed by the chain end and the side chain. Computer simulation to predict segmental density near the chromophore supports the experimental trends. Also photoisomerization of 50% atactic polystyrene (aPS) solutions in toluene and tetrahydrofuran was studied as a function of temperature from 25 deg C to -60 deg C. In aPS / toluene gel, the chain mobilities of the chain center and the chain end showed significant changes near the T sub gel, while side chain and free probe exhibited little change. Effects of concentration and temperature were characterized by bulk viscosity measurement to see how chain mobility is influenced at specific sites. Trans-->cis photoisomerization, Azobenzene labels, Chain center, Chain end, Side chain, Polystyrene solution and gel, Computer simulation, Segment density
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1994
- Accession Number
- ADA281214
Entities
People
- A. Glynn
- Chong S. Sung
- Y. S. Kim
- Yong Hwan Kim
Organizations
- University of Connecticut