2022 Annual Meeting
Dynamics of Styrenic Triblock Copolymer Gels Via Light Scattering
For this research, a measurement technique called dynamic light scattering (DLS) was used to analyze the dynamics of styrenic triblock copolymer gels. Dynamic light scattering is a measurement technique that analyzes the movement of suspended particles through changes in light scattering. By analyzing the correlation in the scattering between a range of time delays, the size and diffusion of the suspended particles can be analyzed. In polymer gels, light scattering behavior is more complicated. Despite this, there are still dynamic modes present in polymer gels that can be analyzed through DLS. The specific polymers used for this research are Styrene-Ethylene-Butylene-Styrene (SEBS) and Styrene-Ethylene-Propylene-Styrene (SEPS). These polymers are unique for their ABA structure that allow the formation of a physically-crosslinked network. This allows gels to form at low copolymer concentrations. The gels were prepared by combining each copolymer with toluene and aliphatic oil at various concentrations. Previous research revealed the existence of three dynamic modes in block copolymer solutions and gels. Two of the dynamic modes are diffusive and more prevalent in solutions (polymer concentrations less than 3%), while the third is a relaxation mode that is more prominent in the gels (polymer concentrations more than 5%). In this research, higher concentration gels (5 to 15%) were analyzed at constant temperature to determine the relationships between the dynamic modes of the gel and the midblock of the copolymer.