Accession Number:

ADA281214

Title:

Mobility Measurement and Computer Simulation at Specific Sites in Polystyrene Solutions and Gels

Descriptive Note:

Technical rept. Jun 1993-May 1994

Corporate Author:

CONNECTICUT UNIV STORRS INST OF MATERIALS SCIENCE

Report Date:

1994-06-01

Pagination or Media Count:

4.0

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

Subject Categories:

  • Organic Chemistry
  • Physical Chemistry
  • Polymer Chemistry

Distribution Statement:

APPROVED FOR PUBLIC RELEASE