Aniline, pyrrole and thiophene substituted with methoxysilyl propyl side chains were investigated by means of spectroscopic and electrochemical techniques. The effect of hydrolysis and ex-situ irradiation of solutions prepared in different solvent mixtures, containing either methanol or methylacetate in excess, was considered also. The development of stable intermediate species in solution is governed by intramolecular polarization of the hydrolyzed monomer rather than by ex-situ photoxidation or electro-oxidation of the monomer head group. Cooperative non-covalent OH-π interactions between the electron deficient silanol (SiOH) and the electron rich aromatic π system leading to mixed- n-p type redox behavior of the hybrid films are confirmed for the case of N-substituted pyrrolyl-silicon derivative. Less efficient interactions of the more basic N-AnSi derivative result from the deprotonation and self-condensation of SiOH, being supported by the prevalent p-type charge transport of the related hybrid film. For the case thiophenyl-silicon derivatives, charge trapping manifesting n-type redox behavior dominates for the case of α-substituted thiophene rather than for the parent β-substituted derivative but with jellification, indicating effective OH-π stabilization of σ-coupled α,α’ dimer structures by a short-range intramolecular mechanism. The establishment and modulation of constructive OH-π interactions determine the macromolecular aggregation and redox behavior of the hybrid films. The diverse properties exhibited by the hybrid precursors support different protection mechanisms against corrosion.
Macromolecular aggregation and electrochemical behavior of pyrrolyl-, anilynyl- and thiophenyl-silicon compounds as precursors for thin hybrid films / G. Conchetto, C.M. Santi, M. Trueba, S.P. Trasatti. - In: PROGRESS IN ORGANIC COATINGS. - ISSN 0300-9440. - 124(2018 Nov), pp. 303-313.
|Titolo:||Macromolecular aggregation and electrochemical behavior of pyrrolyl-, anilynyl- and thiophenyl-silicon compounds as precursors for thin hybrid films|
SANTI, CRISTINA MANUELA (Secondo)
TRUEBA, MONICA (Penultimo) (Corresponding)
TRASATTI, STEFANO PIERPAOLO MARCELLO (Ultimo)
|Parole Chiave:||electrochemistry; semiconducting behavior; silicon-organic hybrid precursors|
|Settore Scientifico Disciplinare:||Settore ING-IND/23 - Chimica Fisica Applicata|
Settore ING-IND/22 - Scienza e Tecnologia dei Materiali
|Progetto:||Laboratorio multifunzionale e centro di formazione per la caratterizzazione e la sperimentazione preapplicativa di smart materials|
|Data di pubblicazione:||nov-2018|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1016/j.porgcoat.2018.05.010|
|Appare nelle tipologie:||01 - Articolo su periodico|