Charge Density Gradients of Polymer Thin Film by Gaseous Phase Quaternization

Yeongun Ko; Stephanie Christau; Regine von Klitzing; Jan Genzer

doi:10.1021/acsmacrolett.9b00930

Charge Density Gradients of Polymer Thin Film by Gaseous Phase Quaternization

ACS Macro Lett. 2020 Feb 18;9(2):158-162. doi: 10.1021/acsmacrolett.9b00930. Epub 2020 Jan 14.

Authors

Yeongun Ko¹, Stephanie Christau², Regine von Klitzing³, Jan Genzer^{1

4}

Affiliations

¹ Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905, United States.
² Department of Chemical Engineering, Biointerfaces Institute, University of Michigan, Ann Arbor, Michigan 48109, United States.
³ Department of Physics, Technische Universität Darmstadt, 64289 Darmstadt, Germany.
⁴ Global Station for Soft Matter, Global Institution for Collaborative Research and Education Hokkaido University, Sapporo, 060-0808, Japan.

PMID: 35638676
DOI: 10.1021/acsmacrolett.9b00930

Abstract

We report on the rapid formation of charge density gradients in polymer films by exposing poly([2-dimethylaminoethyl] methacrylate) (PDMAEMA) films resting on flat silica substrates to methyl iodide (i.e., MI, also known as iodomethane) vapors. We adjust the charge gradient by varying the MI concentration in solution and the process time. The thickness of the parent PDMAEMA film does not affect the diffusion of MI through and the reaction kinetics in the films. Instead, the diffusion of MI through the gaseous phase constitutes the limiting step in the overall process.