Date of Award
5-2025
Degree Type
Honors College Thesis
Academic Program
Polymer Science and Engineering BS
Department
Polymers and High Performance Materials
First Advisor
Sarah E. Morgan, Ph.D.
Advisor Department
Polymers and High Performance Materials
Abstract
Triblock polystyrene-polyisobutylene-polystyrene (PS-PIB-PS) copolymers have widespread applications from thermoplastic elastomers to protective coatings for ballistic applications. The incompatibility between the soft PIB and hard PS phases leads to phase separation and subsequent formation of morphological domains like lamellae and cylinders. The structures are stabilized by physical crosslinks, which can greatly improve the toughness of the triblock systems by preventing chain pullout during tensile deformation. We tailored the morphologies (achieving different morphologies with the same block copolymer) by changing the annealing conditions of the block copolymers. Solvent vapor annealing was used to selectively activate the mobility of a particular block, causing a shift in morphology. Diblock and triblock copolymers were subjected to solvent annealing with solvents that favored each block and analyzed using Small-Angle X-Ray Scattering to determine the resulting morphologies. Our findings demonstrate that solvent and vapor annealing conditions can be strategically tuned to control morphology and long-range order in tri-block copolymers. Both relative solubility of the solvent in the blocks, determined by solubility parameter, and solvent vapor pressure are leveraged to achieve desired morphologies.
Copyright
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Recommended Citation
Loving, Bayleigh Madelin, "Tailoring the morphology of block copolymers via solvent-vapor annealing" (2025). Honors Theses. 1028.
https://aquila.usm.edu/honors_theses/1028