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).

Quantifying Doping Efficiency to Probe the Effects of Nanoscale Morphology and Solvent Swelling in Molecular Doping of Conjugated Polymers

“…To dope the conjugated polymer films, 50 μL of F4TCNQ solution with the desired concentration was directly dropped into the film and dried in a N 2 atmosphere without additional thermal annealing. Assuming the density as 1.0 g/cm 3 for conjugated polymers, − which we estimate contributes at most ∼10% systematic error, we calculate the molar fraction of the dopant ( X F4TCNQ ) as the molar ratio of the applied dopant with the number of thiophene units of the conjugated polymers in the spin-coated films as determined from their film thickness.…”

Virtual Issue on Polymers: Recent Advances from a Physical Chemistry Perspective

“…Kim et al 31 study the in situ polymerization of an important conductive polymer (PEDOT) by molecular dynamic simulations in order to gain insights into the average length and length distribution of polymers. VonWald et al 32 analyze the synthesis process of a class of conjugated polymer brushes via a grafting-from technique by characterizing the initiation and growth of the brush using X-ray photoelectron spectroscopy.…”