Pulsed Plasma Polymerization of Benzaldehyde for Retention of the Aldehyde Functional Group

Abstract

Pulsed plasma polymerization of benzaldehyde is used to produce thin films containing aldehyde functional groups. The effects of pulse peak power, pulse-on time, duty cycle, and monomer pressure on film composition, especially aldehyde functional groups, and surface polarity are examined. Film properties are determined using Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), contact angle measurements, and scanning electron microscopy (SEM). Analysis using these techniques shows retention of the aromatic structure occurs with the longest off times and smallest duty cycles while retention of the aldehyde group occurs only under plasma conditions that result in fragmentation of the aromatic ring, higher peak pulse power, and a relatively large duty cycle (20%).

Structure and Thermal Properties of Thin Film Poly(α‐methylstyrene) Deposited via Plasma‐Enhanced Chemical Vapor Deposition

“…Spectra were baseline corrected and typically taken at 4 cm ±1 resolution averaged over 64 scans. 13 C Solid-state NMR analysis was performed using a home-built spectrometer, consisting of a 6.338 T Oxford superconducting magnet and a 3.2 mm Chemagnetics magic-angle sample spinning (MAS) probe. Approximately 12 mg of sample, collected from a number of identical runs, was scraped off the silicon wafers and packed into a zirconia rotor of internal volume 11 mm 3 .…”

“…Sample spinning at the magic angle of 54.7 was performed to mitigate spectral broadening. The sample spinning speed for 13 C experiments was 15 kHz. 13 C NMR experiments were performed with proton cross-polarization (CP) to enhance the signal and resolution.…”

“…The sample spinning speed for 13 C experiments was 15 kHz. 13 C NMR experiments were performed with proton cross-polarization (CP) to enhance the signal and resolution. The 1 H± 13 C CP time was 3 ms [25], and the 90 pulse width was 1.3 ms. Time between successive scans was 30 s, and spectra were typically acquired for 8±12 h. 13 C spectra were externally referenced to tetramethylsilane (TMS).…”

“…By exposing the monomer only to a brief pulse of radio frequency (RF) energy, it is possible to limit the activation of the reacting species, providing greater control over the reaction pathway. In this manner, it is possible to retain much of the desired functionality of a monomer for inclusion in the polymer, [12,13] providing important benefits in the rational design of polymer functionality. Additionally, by limiting the amount of plasma exposure, the growing film is subjected to less radiation and ion bombardment.…”

A Substrate‐Independent Approach for the Surface Immobilization of Oligonucleotides using Aldehyde Functionalized Surfaces

“…Although previous attempts have been made to plasma-deposit aldehyde groups from precursors such as acrolein, [33][34][35] acetaldehyde, [36] or benzaldehyde, [37] they have all suffered from poor aldehyde group incorporation due to either extensive fragmentation of the monomer or the absence of a polymerizable carboncarbon double bond. …”