Electronic behavior of micro-structured polymer foils immersed in electrolyte

• Published in: Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms Beam interactions with materials and atoms, 2013-07, Vol.306, p.222-226
• Main Authors: Souza, C.T., Stori, E.M., Fink, D., Vacík, V., Švorčík, V., Papaléo, R.M., Amaral, L., Dias, J.F.
• Format: Article
• Language: English
• Subjects: Addition polymerization; Electrical properties; Electrolytes; Electronics; Etching; Foils; Foils (structural shapes); Microstructure; Polymers; Proton beam writing; Proton irradiation
• ISSN: 0168-583X; 1872-9584
• DOI: 10.1016/j.nimb.2012.12.031

The presence of impurities in polymers makes them electroactive. When immersed in electrolytes, polymers can incorporate additional ions, thus changing their electronic properties. The aim of the present work is to characterize the electronic behavior of polymers with microstructures obtained from proton irradiation and etching. To that end, polyethylene terephthalate foils were irradiated with a 2.0×2.0μm2 proton beam of 3MeV. Subsequently, the foils were submitted to an etching procedure with NaOH, leading to microstructures of the order of 1000μm2. Finally, the polymers were immersed in a solution of NaCl and submitted to an AC voltage from a function generator. The results show that the etching procedure after proton irradiation leads to buried structures in the polymers. Pristine and microstructured foils show an Ohmic behavior for frequencies below 1kHz and a capacitive behavior above this frequency up to 1MHz. This behavior is independent of the foil thickness and the area of the structures.