Tratamento em plasmas de triclorometano para a modificação superficial de borrachas de silicone
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Data
2020-06-29
Autores
Turri, Rafael Gustavo [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Diversas amostras de borrachas de silicone foram tratadas em plasmas de CHCl3 em função dos seguintes parâmetros de processo: tempo, potência de radiofrequência aplicada e pressão parcial de CHCl¬3. Os efeitos do tratamento a plasma na modificação superficial da borracha de silicone foram investigados em função do aumento regular de tais parâmetros até um limite de: 75 (s), 150 (W) e 40 (mTorr) de CHCl3. Ângulos de contato e energia de superfície foram medidos empregando Goniometria. O tratamento a plasma aumentou a hidrofilicidade da borracha de silicone, reduzindo o ângulo de contato com a água de aproximadamente 110° para 23°. Adicionalmente foi estudado o efeito do envelhecimento do tratamento a plasma no ângulo de contato e o fenômeno de recuperação hidrofóbica. Medidas de rugosidade aritmética e quadrática foram tomadas por meio da técnica de Perfilometria. A estrutura química da borracha tratada foi investigada a partir das técnicas de Espectroscopia de Infravermelho por Transformada de Fourier (FTIR) e por Espectroscopia no Infravermelho com Modulação de Polarização (PM-IRRAS). A composição química das amostras tratadas foi verificada a partir da técnica de Espectroscopia de Raios-X por dispersão em Energia (EDS). A morfologia das amostras tratadas foi examinada por meio das técnicas de Microscopia Eletrônica de Varredura (SEM) e Microscopia de Força Atômica (AFM). A análise química quantitativa da superfície das amostras foi obtida por meio de análises de Espectroscopia de Foto Elétrons de Raios-X (XPS). A redução no ângulo de contato superficial é um efeito provocado pela oxidação da superfície da borracha conforme observado nas análises de XPS e na presença de compostos de Si-Ox identificados nas análises de PM-IRRAS. As análises de envelhecimento de ângulo de contato e XPS em atmosfera controlada de argônio revelaram que a oxidação superficial não é um efeito exclusivamente relacionado a exposição do material tratado ao oxigênio do ar atmosférico.
Seriesof silicon rubbersamples were treated in CHCl3plasmas based on process parameters such as:time, radiofrequency power and CHCl3partial pressure. The effects of plasma treatment on the superficial modification of the silicone rubber were investigated as afunction of steady increase of theseparametersuntil the limit of: 75 (s), 150 (W) and40 (mTorr) ofCHCl3. Surfacecontact anglesandsurface energies were measured using Goniometry.Surface treatments succeeded in increasing the hydrophilicityof silicone rubber, reducing the water contact angle from approximately 110° to 23°. Additionally, the effect of plasma treatment aging inthe contact angleand also the hydrophobic recoverywasstudied. Measurements of arithmetic and quadraticroughness were carried out using Profilometry. Chemical groups present inthe rubber were investigatedusing Fourier Transform Infrared Spectroscopy (FTIR) and Infrared Spectroscopy with Polarization Modulation (PM-IRRAS). The chemical composition of the samples was verified using the Energy Dispersion X-Ray Spectroscopy (EDS). Surfacemorphology of the treated and untreatedspecimens was examined by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM).A quantitative chemical analysis of the high surface was obtained by X -Ray Electron Spectroscopy (XPS). The reduction in the surface contact angle is an effect caused by the oxidation of the rubber surface as shown bythe XPS analyzesand also in the presence of SI-Ox.as identified in PM-IRRAS analysis.The aging of contact angle and XPS analysis from samples placed in a controlled argon atmosphere revealed that surface oxidation is not an exclusive effect related to treated materialexposure to oxygen in atmospheric air.
Seriesof silicon rubbersamples were treated in CHCl3plasmas based on process parameters such as:time, radiofrequency power and CHCl3partial pressure. The effects of plasma treatment on the superficial modification of the silicone rubber were investigated as afunction of steady increase of theseparametersuntil the limit of: 75 (s), 150 (W) and40 (mTorr) ofCHCl3. Surfacecontact anglesandsurface energies were measured using Goniometry.Surface treatments succeeded in increasing the hydrophilicityof silicone rubber, reducing the water contact angle from approximately 110° to 23°. Additionally, the effect of plasma treatment aging inthe contact angleand also the hydrophobic recoverywasstudied. Measurements of arithmetic and quadraticroughness were carried out using Profilometry. Chemical groups present inthe rubber were investigatedusing Fourier Transform Infrared Spectroscopy (FTIR) and Infrared Spectroscopy with Polarization Modulation (PM-IRRAS). The chemical composition of the samples was verified using the Energy Dispersion X-Ray Spectroscopy (EDS). Surfacemorphology of the treated and untreatedspecimens was examined by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM).A quantitative chemical analysis of the high surface was obtained by X -Ray Electron Spectroscopy (XPS). The reduction in the surface contact angle is an effect caused by the oxidation of the rubber surface as shown bythe XPS analyzesand also in the presence of SI-Ox.as identified in PM-IRRAS analysis.The aging of contact angle and XPS analysis from samples placed in a controlled argon atmosphere revealed that surface oxidation is not an exclusive effect related to treated materialexposure to oxygen in atmospheric air.
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Palavras-chave
Triclorometano, Borracha de silicone, Modificação superficial, Tratamento a plasma, Plasma treatment, Trichloromethane, Silicone rubber, Surface modification