Branched Fluoropolymer−Si Hybrids via Surface-Initiated ATRP of Pentafluorostyrene on Hydrogen-Terminated Si(100) Surfaces

Abstract

Linear, branched, and arborescent fluoropolymer-Si hybrids were prepared via surface-initiated atom transfer radical polymerization (ATRP) from the 4-vinylbenzyl chloride (VBC) inimer and ClSO(3)H-modified VBC that were immobilized on hydrogen-terminated Si(100), or Si-H, surfaces. The simple approach of UV-induced coupling of VBC with the Si-H surface provided a stable, Si-C bonded monolayer of "monofunctional" ATRP initiators (the Si-VBC surface). The aromatic rings of the Si-VBC surface were then sulfonated by ClSO(3)H to introduce sulfonyl chloride (-SO(2)Cl) groups and to give rise to a monolayer of "bifunctional" ATRP initiators. Kinetics study indicated that the chain growth of poly(pentafluorostyrene) from the functionalized silicon surfaces was consistent with a "controlled" or "living" process. The chemical composition and functionality of the silicon surface were tailored by the well-defined linear and branched fluoropolymer brushes. Atomic force microscopy images revealed that the surface-initiated ATRP of pentafluorostyrene (PFS) had proceeded uniformly on the Si-VBC surface to give rise to a dense and molecularly flat surface coverage of the linear brushes. The uniformity of surfaces with branched brushes was controlled by varying the feed ratio of the monomer and inimer (VBC in the present case). The living chain ends on the functionalized silicon surfaces were used as the macroinitiators for the synthesis of diblock copolymer brushes, consisting of the PFS and methyl methacrylate polymer blocks.

Highly Luminescent Covalently Linked Silicon Nanocrystal/Polystyrene Hybrid Functional Materials: Synthesis, Properties, and Processability

“…[50][51][52] Xu et al investigated surface initiated atom transfer radical polymerization (ARTP) on Si surfaces derived from mono layer modifi cation of hydride and halogen terminated silicon and effectively induced the formation of polymer brushes grafted surface. [ 53,54 ] Similarly, Zhang et al reported a rapid grafting method to grow thick and dense polymer brushes on silicon using a multiple-step functionalization including UV-induced hydrosilylation followed by rare metal catalyzed polymerization. [ 55 ] All of these reports provide a basis for the preparation of SiNC/polymer hybrids, however many employ metal catalysts or reaction conditions that could compromise favorable SiNC properties.…”

Molecular Aggregation State of Surface-grafted Poly{2-(perfluorooctyl)ethyl acrylate} Thin Film Analyzed by Grazing Incidence X-ray Diffraction

“…The influence of the branching structure of polymer brush on surface wettablity was investigated by Kang et al, who prepared branched fluoropolymer brush using 2,3,4,5,6-pentafluorostyrene (PFS) and 4-vinylbenzyl chloride as an inimer. 18 They reported that the water contact angle depends on the composition of the fluoropolymer block and inimer, and that the surface roughness is caused by the branching structure of the brush. Surface rearrangement properties upon solvent and thermal treatment were observed on polystyrene-block-PFA-C 8 and polystyrene-block-poly(PFS) brushes.…”

Covalent Immobilization of Glucose Oxidase on Well-Defined Polymer-Silicon Wafer Hybrids via Surface-Initiated Raft-Mediated Process

“…26 The static water contact angles of the pristine and functionalized Si-H surfaces were measured at 25 °C and 60% relative humidity on a telescopic goniometer (Rame-Hart model 10000-230, Moutain Lake, NJ, USA). For each angle reported, at least four measurements from different surface locations were averaged.…”