XPS Study of the Chemical Structure of Plasma Biocopolymers of Pyrrole and Ethylene Glycol

Abstract

An XPS study about the structure of plasma biocopolymers synthesized with resistive radio frequency glow discharges and random combinations of ethylene glycol, pyrrole, and iodine, as a dopant, is presented in this work. The collisions of molecules produced structures with a great variety of chemical states based in the monomers, their combinations, crosslinking, doping, fragmentation, and oxidation at different levels in the plasma environment. Iodine appears bonded in the copolymers only at high power of synthesis, mainly as C-I and N-I chemical bonds. Multiple bonds as C≡C, C≡N, C=O, and C=N were found in the copolymers, without belonging to the initial reagents, and were generated by dehydrogenation of intermediate compounds during the polymerization. The main chemical states on PEG/PPy/I indicate that all atoms in pyrrole rings participate in the polymerization resulting in crosslinked, partially fragmented, and highly oxidized structures. This kind of analysis can be used to modify the synthesis of polymers to increase the participation of the most important chemical states in their biofunctions.

Effect of different exposure times on physicochemical, mechanical and biological properties of PGS scaffolds treated with plasma of iodine-doped polypyrrole

“…A band centered at 2200 cm −1 attributed to the C ≡N and a wide band at 1620 cm −1 attributed to the C = C and N-H bonds were also observed. 26,27 The bands centered at 1400 cm −1 and at 525 cm −1 can be associated with the substitution of hydrogens in heteroaromatic rings, showing the presence of iodine, as was previously reported; the first one is attributed to the stretching vibration of the CI=CH 2 group and the second one to the C-I bond. 28–30 The FTIR spectrum of untreated PGS scaffolds showed a wide band centered at 3500 cm −1 attributed to the stretching vibrations of the O-H bonds, and two bands at 2930 cm −1 and 2850 cm −1 assigned to the stretching vibrations of the C-H group.…”

Photocatalytic cyanation of carbon nitride scaffolds: Tuning band structure and enhancing the performance in green light driven C S bond formation

“…[27] Moreover, thiocyanate salts, which could be converted to cyanides by oxidation, are widely used as a safe cyanation reaction reagent. [31][32][33] Inspired by those facts, we employed thiocyanate salt as the cyano group source via a facile photocatalytic reaction. In this strategy, the thiocyanate ion is first photocatalytically converted to cyano radical by carbon nitride; which recombines with the carbon nitride scaffold afterwards, forming cyanidated g-C3N4 (g-C3N4-xCN, where x represents the content of CN group in the sample by weight percentage).…”

Chemical States of Plasma Polypyrrole Coatings on Stainless Steel Stents

“…C1s was adjusted using 5 curves with FWHM (Full Width at Half Maximum) = 1.0 ± 0.1 eV; N1s was adjusted with 4 curves with FWHM = 1.2 ± 0.1 eV and O1s was adjusted with 3 Gaussian curves with FWHM = 1.4 ± 0.1 eV . Figures a–c show plots with the participation percentage and the maximum binding energy (BE) of each Gaussian curve associated with specific chemical states . The states were assigned considering all possible chemical bonds of each element, C = 4, N = 3 and O = 2, with the surrounding atoms.…”