Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/348828
Type: Artigo
Title: Triboelectricity: macroscopic charge patterns formed by self-arraying ions on polymer surfaces
Author: Burgo, Thiago A. L.
Ducati, Telma R. D.
Francisco, Kelly R.
Clinckspoor, Karl J.
Galembeck, Fernando
Galembeck, Sergio E.
Abstract: Tribocharged polymers display macroscopically patterned positive and negative domains, verifying the fractal geometry of electrostatic mosaics previously detected by electric probe microscopy. Excess charge on contacting polyethylene (PE) and polytetrafluoroethylene (PTFE) follows the triboelectric series but with one caveat: net charge is the arithmetic sum of patterned positive and negative charges, as opposed to the usual assumption of uniform but opposite signal charging on each surface. Extraction with n-hexane preferentially removes positive charges from PTFE, while 1,1-difluoroethane and ethanol largely remove both positive and negative charges. Using suitable analytical techniques (electron energy-loss spectral imaging, infrared microspectrophotometry and carbonization/colorimetry) and theoretical calculations, the positive species were identified as hydrocarbocations and the negative species were identified as fluorocarbanions. A comprehensive model is presented for PTFE tribocharging with PE: mechanochemical chain homolytic rupture is followed by electron transfer from hydrocarbon free radicals to the more electronegative fluorocarbon radicals. Polymer ions self-assemble according to Flory–Huggins theory, thus forming the experimentally observed macroscopic patterns. These results show that tribocharging can only be understood by considering the complex chemical events triggered by mechanical action, coupled to well-established physicochemical concepts. Patterned polymers can be cut and mounted to make macroscopic electrets and multipoles
Subject: Polímeros
Country: Estados Unidos
Editor: American Chemical Society
Rights: Fechado
Identifier DOI: 10.1021/la301228j
Address: https://pubs.acs.org/doi/10.1021/la301228j
Date Issue: 2012
Appears in Collections:IQ - Artigos e Outros Documentos

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