Initiation and Polymer Density of Conjugated Polymer Brushes

Abstract

The growth mechanism and polymer density in conjugated polymer brush (CPB) films composed of poly(3-methylthiophene) (P3MT) are characterized. X-ray photoelectron spectroscopy experiments show that the initiation of aryl halide monolayers by Pd(PtBu3)2 produces disproportionated monolayer initiators. Unlike disproportionated species formed during the solution-phase initiation of aryl halides, which cannot mediate polymerization, the surface-bound initiators catalyze polymerization to form CPB films with a high grafting density (1.2 nm–2). Rutherford backscattering spectrometry (RBS) experiments show that P3MT CPB films have a characteristic monomer volume density (3.7 nm–3) that is indistinguishable from the volume density of spuncast poly(3-hexylthiophene) films. Using these RBS and XPS results, characteristics of P3MT CPB growth are obtained, including the turnover frequency (7.5 h–1) and polymer molecular weight (300 g/mol·nm).

Citation

Initiation and Polymer Density of Conjugated Polymer Brushes

Ian A. VonWald, S. Gaither Frye, Mark M. Moog, Carrie L. Donley, Frank Tsui, and Wei You
The Journal of Physical Chemistry B 2020 124 (43), 9734-9744
DOI: 10.1021/acs.jpcb.0c06923