Artigo
Synthesis of poly(styrene-co-methyl methacrylate)-based ionomers and their Langmuir and Langmuir-Blodgett (LB) film formation
Fecha
2004-06-03Registro en:
Journal of Physical Chemistry B. Washington: Amer Chemical Soc, v. 108, n. 22, p. 7033-7039, 2004.
1520-6106
10.1021/jp049778n
WOS:000221700300023
Autor
Universidade de São Paulo (USP)
Universidade Estadual Paulista (Unesp)
Resumen
Poly(styrene-co-methyl methacrylate) (PS-PMMA) ionomers with several degrees of sulfonation were synthesized and characterized by infrared, UV-vis, and NMR spectroscopies, elemental analysis, and differential scanning calorimetry (DSC). Stable Langmuir films could be produced with PS-PMMA with 3 and 6 mol % of sulfonation, while PS-PMMA 8% exhibited material loss to the water subphase, probably due to its higher solubility. Surface pressure and surface potential isotherms with PS-PMMA 3% spread onto salt-containing subphases pointed to a film behavior characteristic of the polyelectrolyte effect, where charge repulsion governs the film properties. The Langmuir-Blodgett films of this ionomer were successfully transferred onto various substrates, as confirmed by UV-vis and FTIR spectroscopies. Using cycling voltammetry, we show that LB films from PS-PMMA 3% can be applied in selective sensing of dopamine, even in the presence of interferents such as ascorbic acid.