Synthesis and self-assembly of the amphiphilic homopolymers poly(4-hydroxystyrene) and poly(4-(4-bromophenyloxy)styrene)

Abstract

Poly(4-(1-ethoxyethoxy)styrene) was synthesized by living anionic polymerization under high vacuum conditions. Amphiphilic derivatives, poly(4-hydroxystyrene) (PHS) and poly(4-(4-bromophenyloxy)styrene) (PBPOS) were synthesized by post-polymerization reactions of poly(4-(1-ethoxyethoxy)styrene). For comparison of hydrogen bonding and halogen bonding, the self-assembly behaviors of both homopolymers, PHS and PBPOS, were evaluated by dynamic/static light scattering (DLS/SLS) in a mixed solvent of water : tetrahydrofuran and water : methanol, respectively. The morphologies of aggregates were recorded using atomic force microscopy (AFM), scanning electron microscope (SEM), and transmission electron microscopy (TEM). PHS forms the hollow micelles in the water : THF mixed solvent and the vesicles in the water : methanol mixed solvent. Also, PBPOS forms the open-mouth vesicles in the water : methanol mixed solvent. PHS vesicles show potential as a template for forming gold nanoparticles and can act as a reservoir of the anti-cancer drug doxorubicin. The release of doxorubicin from PHS vesicles depends on the pH of the release media. The rate of drug release is higher at basic pH. The viability of the colon cancer cell line HCT-116 decreased by 27% compared to an untreated cell line when treated with doxorubicin loaded PHS vesicles.