open access

https://hdl.handle.net/2115/79126

Spontaneous Degrafting of Weak and Strong Polycationic Brushes in Aqueous Buffer Solutions

英語

Polymers

2019-08-27

American Chemical Society

Macromolecules

52(16)

6192-6200

Polymers grafted to substrates have traditionally been considered stable because of the covalent bonds that hold the polymers attached to the substrate. However, several recent reports have indicated that grafted polymers may detach from substrates under specific conditions. In this work, we report on a systematic study of polymer degrafting involving polycationic brushes with different degrees of quaternization (DQ, mol %), which have been incubated in three different buffer solutions (pH 4, 7.4, and 9) with the same ionic strength of 0.05 M. We have varied the molecular weight (MW) and grafting density (σ) of the polymer brushes using a combinatorial setup to examine the effect of MW, σ, and DQ on polymer degrafting. Furthermore, we explored the effect of the bonding environment at the base of the initiator (mono- vs. tri-functional) of the grafted polymer layer at the substrate on the overall stability of polymer brushes on the substrate. The two major findings in this paper are (1) degrafting of polycationic grafts from flat silica substrate increases with increasing DQ of the polymer and (2) polymer degrafting likely occurs both in the initiator ester group and the silane head-group at the silicon substrate.

学術雑誌論文

Accepted Manuscript

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Macromolecules, copyright c American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/doi/10.1021/acs.macromol.9b01362.

0024-9297

1520-5835