Construction of micelles and hollow spheres via the self-assembly behavior of poly(styrene- alt-p HPMI) copolymers with poly(4-vinylpyridine) derivatives mediated by hydrogen bonding interactions.

This study describes the preparation of hydrogen bonding connected micelles, consisting of a poly(styrene- alt -( para -hydroxyphenylmaleimide)) [poly(S- alt -pHPMI)] core and a poly(4-vinylpyridine) (P4VP) derivative shell in a selective solvent. The aim was to modify hydrogen bonding interaction sites at the core/shell interface by synthesizing P4VP derivatives in three different sequences, namely, P4VP homopolymers, PS- co -P4VP random copolymers, and block copolymers. TEM images showed the successful self-assembly of poly(S- alt -pHPMI)/PS- co -P4VP inter-polymer complexes into spherical structures. To dissolve the core structures, 1,4-dibromobutane was used as a cross-linking agent to tighten the PS- co -P4VP shell. The morphologies, particle sizes, hydrogen bonding, cross-linking reaction, and core dissolution were confirmed by TEM, DLS, FTIR, and AFM analyses. Poly(S- alt-p HPMI)/PS 41 - r -P4VP 59 hydrogen bonding connected micelles, cross-linked micelles, and hollow spheres were larger and more irregular than poly(S- alt-p HPMI)/P4VP inter-polymer complexes due to the random copolymer architecture and the decrease in intermolecular hydrogen bonds. However, poly(S- alt-p HPMI)/PS 68 - b -P4VP 32 resulted in rod- or worm-like structures after core dissolution.