The additive effects in matrix dispersed liquid crystals

Detalhes bibliográficos
Autor(a) principal: Melo, Carlos Alberto da Silva Ribeiro de
Data de Publicação: 2009
Tipo de documento: Dissertação
Idioma: eng
Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
Texto Completo: http://hdl.handle.net/10362/10683
Resumo: Dissertation presented at Faculdade de Ciências e Tecnologia from Universidade Nova de Lisboa to obtain the degree of Master in Chemical and Biochemical Engineering
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spelling The additive effects in matrix dispersed liquid crystalsDissertation presented at Faculdade de Ciências e Tecnologia from Universidade Nova de Lisboa to obtain the degree of Master in Chemical and Biochemical EngineeringThe main objective of this work was to optimize the structure of a matrix that will support a nematic mixture of liquid crystals, known as 7 from Merck, in order to produce a matrix dispersed liquid crystal device with good electro-optical responses. The composites are based on monomers, such as tri(ethylene glycol) dimethacrylate and poly(ethylene glycol) dimethacrylate with typical molecular weight of 875 . −1 with two different types of polymerization, a thermal polymerization with initiation by α,α’-azoisobutyronitrile and a photochemical polymerization with initiation by p-xyleneN,N diethyldithiocarbamate. To do that, some additives have been used as a way to format the shape and the size of the liquid crystal microdroplets and to avoid its coalescence and, therefore, optimizing the performance of the device as being able to electro-optical application. Octanoic acid, ethylene glycol, triton X-100, cetyl trimethyl ammonium bromide and sodium dodecyl sulfate have been used as additives to the systems. Different aspects were investigated, such as the study of the dynamics of the transition ON/OFF state using a high-frequency alternate voltage and the attempt to minimize and maximize the liquid crystal anchorage breaking to the polymer matrix observed when tension is applied. The polymer morphology and the composites synthesized were analyzed by polarized optical microscopy and scanning electron microscopy and those results were related with the electro-optical response curves of the composites in study. The best results were obtained with the system containing the triton X-100 as an additive, thus this system was analyzed with additional studies of differential scanning calorimetry, dielectric relaxation spectroscopy and a scanning temperature through polarized optical microscopy.Fundação para a Ciência e Tecnologia - project PTDC/CTM/69145/2006Faculdade de Ciências e TecnologiaSotomayor, JoãoRUNMelo, Carlos Alberto da Silva Ribeiro de2013-11-06T14:48:24Z20092009-01-01T00:00:00Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisapplication/pdfhttp://hdl.handle.net/10362/10683enginfo:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2024-03-11T03:44:34Zoai:run.unl.pt:10362/10683Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-20T03:19:39.607525Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse
dc.title.none.fl_str_mv The additive effects in matrix dispersed liquid crystals
title The additive effects in matrix dispersed liquid crystals
spellingShingle The additive effects in matrix dispersed liquid crystals
Melo, Carlos Alberto da Silva Ribeiro de
title_short The additive effects in matrix dispersed liquid crystals
title_full The additive effects in matrix dispersed liquid crystals
title_fullStr The additive effects in matrix dispersed liquid crystals
title_full_unstemmed The additive effects in matrix dispersed liquid crystals
title_sort The additive effects in matrix dispersed liquid crystals
author Melo, Carlos Alberto da Silva Ribeiro de
author_facet Melo, Carlos Alberto da Silva Ribeiro de
author_role author
dc.contributor.none.fl_str_mv Sotomayor, João
RUN
dc.contributor.author.fl_str_mv Melo, Carlos Alberto da Silva Ribeiro de
description Dissertation presented at Faculdade de Ciências e Tecnologia from Universidade Nova de Lisboa to obtain the degree of Master in Chemical and Biochemical Engineering
publishDate 2009
dc.date.none.fl_str_mv 2009
2009-01-01T00:00:00Z
2013-11-06T14:48:24Z
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
dc.type.driver.fl_str_mv info:eu-repo/semantics/masterThesis
format masterThesis
status_str publishedVersion
dc.identifier.uri.fl_str_mv http://hdl.handle.net/10362/10683
url http://hdl.handle.net/10362/10683
dc.language.iso.fl_str_mv eng
language eng
dc.rights.driver.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv Faculdade de Ciências e Tecnologia
publisher.none.fl_str_mv Faculdade de Ciências e Tecnologia
dc.source.none.fl_str_mv reponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação
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repository.name.fl_str_mv Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação
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