Date of Award
Master of Science
Chemical and Biological Engineering
Eric W. Cochran
Polymer self-assembly structures are of great interest for their nanoscale ordered microstructure. Several frontier studies have successfully utilized these self-assemble structure for multiple applications. Especially the vesicle, it is formulated by self-assembly of block copolymer during blending with other media. However, due to limited solvents selection and the difficulty to protect the vesicles after solvents removal, isolating the vesicles from solvent for further potential applications is impossible. In this work, we provide a general method to provide isolatable hollow-core polymeric vesicles by polymer blend. We select poly(isoprene-b-simethylsiloxane) (PI-b-PDMS) di-block copolymer (di-BCP) as the vesicle formation material. The PI-b-PDMS was first blending with PDMS homopolymer as matrix, then the PI block was crosslinked by dicumyl peroxide as thermal crosslinking initiator. The PDMS matrix in the mixture can be separated by using dialysis to provide isolated hollow-core vesicles. Transmission electron microscope (TEM) and small angle x-ray scattering were used to investigate the morphology of as-blended, as-crosslinked and dialyzed samples, which indicate the vesicles were able to be formed by PI-b-PDMS self-assembly. Also, the self-assembly structure can be protected after crosslinking and dialysis. Dynamic light scattering (DLS) measurement of as-blended and as-crosslinked samples dispersed in tetrahydrofuran provided the evidence of vesicles were successfully crosslinked by thermal crosslinking. Energy disperse spectroscopy (EDS) microelemental analysis results under TEM indicate present work successfully removed the PDMS matrix from the core of vesicles. We also mixed isolated hollow-core vesicles as fillers with crosslinkable PDMS matrix to evaluate the possibility of using the method provided from present work for future application on providing porous polymer or other potential applications.
Wang, Tung-ping, "Preparation and characterization of block copolymer modified nanocomposite" (2019). Graduate Theses and Dissertations. 17603.
Available for download on Saturday, July 24, 2021