Plasma Sanitizers on Flexible Substrates

• Autor(a) principal: Sousa, Inês Gaspar Melo e Castro Costa de
• Data de Publicação: 2021
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/134703
• topic: low-temperature plasma; dielectric barrier discharge; plasma generators; reactive species; surface modification; Domínio/Área Científica::Engenharia e Tecnologia::Nanotecnologia

Technologies related to low-temperature plasma have gained tremendous importance in recent years due to the numerous advantages they present. These types of treatments allow modifying surfaces without changing their volume properties, in a durable way and according to affordable processes. The mixture of reactive species that cold plasma produces also makes it possible to disinfect surfaces and treat biological tissues. However, the existing cold plasma production techniques are expensive, polluting, and use rigid components that cannot conform to irregular surfaces. To overcome those limitations, this dissertation's objective consists of production, optimization, and testing plasma generators that take advantage of the principle of dielectric barrier discharge (DBD). The generators developed were produced by two methods, a laser made shadow mask and inkjet printing process, and consist of a structure with one or two electrodes. Three different types of paper were used as the DBD dielectric layer: two commercial papers used for printed electronics, Felix Schoeller smart type 3 and Powercoat ™ XD 125, and a third one mostly used for drawing purposes, Canson vegetal paper. It has been proven that generators patterned by a laser made shadow mask and by inkjet printing can generate plasma in a vacuum chamber, in a pressure range of 0.55 to 10.5 Torr (23 to 1400 Pa) and with a power range from 2 to 16W. It is shown that generators with two electrodes can confine plasma better than the ones using a single electrode. Also, it was observed that the gas atmosphere, patterning method, and structure of the paper influences the lifetime of the paper-based generators. Moreover, it was noticed that the generators made with vegetal paper and powercoat XD paper withstand for a longer period of time. The use of plasma generators for surface modification was tested on different surfaces. The wettability of cork, vegetal paper, and spinach leaf surfaces was assessed for different plasma times.