Conformation of Adsorbed Random Copolymers:  A Solid-State NMR and FTIR-PAS Study

Abstract

The properties of bulk and adsorbed polyethylene-co-acrylic acid (PEA) random copolymers were characterized by solid-state NMR and vibrational spectroscopy. FTIR-PAS (Fourier transform infrared photoacoustic spectroscopy) measurements show that the copolymers are chemisorbed to zirconia surfaces via the carboxylic acid sticker groups. The chain mobility, conformation, and morphology of bulk and adsorbed PEA were studied by 13 C CP-MAS, 2D WISE, and 1 H spin diffusion NMR experiments. The effect of the copolymer loading and acrylic acid content on these properties was examined. Whereas adsorbed PEA with a 5% w/w acrylic acid content contain transoid chain segments at all loadings, samples with higher acrylic acid contents (15 % w/w) only display an all-trans component at higher loadings where unbound acid groups are present.

Characterization of polyelectrolyte effect in poly(acrylic acid) solutions

“…Yin et al studied the swelling of this class of polymers jointly with their biodegradation in controlled drug‐release systems 14. Nasredinne et al studied the conformation of acrylic acid based copolymers using NMR and FTIR spectroscopy 15. In the specific case of this work, we will study the polyelectrolyte effect in poly(acrylic acid) solutions as a function of the addition of the neutralizing agent KOH.…”

“…14 Nasredinne et al studied the conformation of acrylic acid based copolymers using NMR and FTIR spectroscopy. 15 In the specific case of this work, we will study the polyelectrolyte effect in poly(acrylic acid) solutions as a function of the addition of the neutralizing agent KOH. This will be done by the determination of reduced viscosity and conductivity as a function of polymer concentration at different KOH/COOH ratios without the isoionic approach to the problem.…”

Bound fractions of methacrylate polymers adsorbed on silica using FTIR

“…The utility of FTIR is not limited to bulk polymers; polymer composites can also be characterized 20, 21. Variants of the technique, such as attenuated total reflection (ATR)22, 23 and photoacoustic spectroscopy,24 can also be useful for studying composite interfaces. Quantitative analysis with FTIR, however, requires knowledge of a number of parameters as well as calibration plots, and it is sometimes difficult to determine the necessary parameters.…”

Bound carbonyls in PMMA adsorbed on silica using transmission FTIR

“…The versatility of FTIR has allowed several different variants to be used in determining bound fractions, usually carbonyls, in adsorbed polymers. Attenuated total‐reflection Fourier‐transform infrared (ATR‐FTIR) spectroscopy,7–9 external reflection,4 Fourier‐transform infrared photoacoustic spectroscopy (FTIR‐PAS),10 and dispersive IR2 have all been used for this purpose. The FTIR‐PAS and reflection FTIR techniques have been used for solid samples, but both techniques require specialized accessories and accurate quantification of to those results may be difficult.…”