Head-to-Tail and Head-to-Head Molecular Chains of Poly(-Anisidine): Combined Experimental and Theoretical Evaluation.

Poly(-anisidine) (PPA) is a polyaniline derivative presenting a methoxy (-OCH) group at the position of the phenyl ring. Considering the important role of conjugated polymers in novel technological applications, a systematic, combined experimental and theoretical investigation was performed to obtain more insight into the crystallization process of PPA. Conventional oxidative polymerization of -anisidine monomer was based on a central composite rotational design (CCRD).

Poly(-methoxyaniline) Chain Degradation Based on a Heat Treatment (HT) Process: Combined Experimental and Theoretical Evaluation.

Poly(-methoxyaniline) emeraldine-salt form (ES-POMA) was chemically synthesized using hydrochloric acid and subjected to a heat treatment (HT) process for 1 h at 100 °C (TT) and 200 °C (TT). The HT process promoted a progressive decrease in crystallinity. The Le Bail method revealed a decomposition from tetrameric to trimeric-folded chains after the HT process.

Vibrational Spectra of Atmospherically Relevant Hydrogen-Bonded MSA···(HSO) ( = 1-3) Clusters.

Methanesulfonic acid (CHSOH), also known as MSA, has been found to be capable of forming a strong hydrogen-bonded interaction with sulfuric acid (HSO) under ambient conditions. The energetic stability of the MSA···HSO clusters increases with decreasing temperature at higher altitudes in the troposphere, which is relevant in the context of atmospheric aerosol formation. We have performed, in the present work, a detailed and systematic quantum-chemical calculation with high-level density functional theory to characterize the hydrogen bond formation in the binary MSA···HSO, ternary MSA···(HSO), and quaternary MSA···(HSO) clusters.

Atmospherically Relevant Hydrogen-Bonded Interactions between Methanesulfonic Acid and HSO Clusters: A Computational Study.

A detailed and systematic quantum-chemical calculation has been performed with high-level density functional theory (DFT) to analyze the electrostatic interaction of methanesulfonic acid (CHSOH), also known as MSA, with pre-formed clusters of sulfuric acid (HSO) molecules in ambient conditions. Both MSA and HSO are considered as atmospheric molecules that might play active roles in aerosol formation. The interactions between MSA and HSO clusters lead to the formation of MSA···(HSO) ( = 2, 3) complexes stabilized by the formation of different types of intermolecular hydrogen bond networks.