Structure of Plasma‐Deposited Poly(acrylic acid) Films

Abstract

Poly(acrylic acid) films with a thickness of about 150 nm were deposited using a pulsed plasma onto aluminum and glass. The structure/property relationships of these samples were studied in dependence to the duty cycle (DC) of the plasma by a broad combination of different techniques and probes. For the first time, volume sensitive methods (FTIR, dielectric spectroscopy, and differential scanning calorimetry) are combined with surface analyses i.e. XPS. For an unambiguous identification of COOH groups by XPS, derivatization with trifluoroethanol was accomplished. Quantitative FTIR investigations give qualitatively a dependence of the concentration of COOH groups upon DC similar to that given by XPS investigations. The observed differences are discussed considering the different analytical depths of both methods. The dielectric measurements reveal that the structure of the plasma deposited films is different from that of the bulk material. Moreover, these measurements show also that the plasma deposited films are not thermally stable but undergo a post plasma chemical reaction during heating, where the reaction kinetics depends on DC.

Structure of Plasma Poly(Acrylic Acid): Influence of Pressure and Dielectric Properties

“…It was about 140 nm for all samples. A more detailed description and illustration of the apparatus was presented in a previous publication elsewhere [9].…”

“…To estimate the concentration of carboxylic groups on the surface, a derivatization of samples with trifluoroethanol (TFE) was performed and followed by a subsequent XPSdetection of the introduced labels as described elsewhere [9,24]. By this method only the COOH groups were converted in ones containing Fluorine (F) atoms which are not present at the original surface.…”

“…Earlier investigations focused on retaining carboxylic acid functionalities of carboxyl-containing monomers in the deposits. In addition, many researchers are attempting to investigate the plasma-phase chemistry to understand the mechanism of the resultant surface chemistry [6][7][8][9][10].…”

Reaction of CO2Gas with (radicals in) Plasma-Polymerized Acrylic Acid (and Formation of COOH-Rich Polymer Layers)

“…[14][15][16][17][18][19][20] CO 2 is a nontoxic, nonflammable, abundant, and renewable feedstock and its biotransformation into industrially important chemicals can not only have a positive impact on the global carbon balance but also provide novel routes for the green biotechnology. As one of the oldest life forms on earth, microalgae have a very high-CO 2 biofixation capacity, grow fast, and accumulate large quantities of lipids and carbohydrates, and hence became the most promising feedstock for production of next generation biofuels like, biodiesel and bioethanol.…”

Pretreatments of Textiles Prior to Dyeing: Plasma Processing

“…In particular, the FTIR spectrum shows that the film contains a high density of C(O)OH groups. The absorption peaks assignment is given in table below (Alaa et al, 2011;Cho et al, 1990;Chilcoti and Ratner, 1993;Eun-Young Choi and Seung-Hyeon Moon, 2007;Jafari et al, 2006;Mirzadeh et al, 2002 2800 to 3800 a broad OH stretching absorption band due to monomeric and dimeric C(O)OH Table 1. IR peak assignment of PPAA It has been observed that our result of plasma polymerization of acrylic acid is in relevance with the literature.…”