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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Polymer-based conductive fibers

Karlsson, Fredrik, Söderlöv, Erik January 2016 (has links)
Conductive polymers, since from their discovery, have become a prominent area of research and found many useful applications in all fields of our daily life. Examples are light emitting diodes, heat generation, chemical sensors and electro-active membranes. Polymer coated textile substrates give flexible and lightweight materials. One well utilized and thoroughly explored conductive polymer is poly(3,4-ethylenedioxythiophene) also known as PEDOT. Although there are different ways to produce PEDOT one of the most common is the VPP technique. The typical procedure when using VPP is to introduce the monomer vapor to an oxidant coated substrate so that it polymerizes on the surface of the substrate. Throughout this study, the VPP technique has been used to produce PEDOT on different textile fibers. Aim was first of all optimizing the process gaining low electric resistance, i. e. high conductivity, of produced coated fibers but also multilayer coatings of fibers. Outcome indicates some parameters not having a clear influence over the results while others had a more distinct impact. A noteworthy result was obtained by coating a substrate, namely lyocell fiber, multiple times with layers deposited directly on each other. This decreased the resistance from 5.1 (± 1.6) kΩ/10 cm to 1.0 (± 0.1) kΩ/10 cm, for one layer and multiple layers respectively. Adding 15 wt. % of the copolymer PEG-PPG-PEG to the oxidant solution decreased the resistance from 6.8 (± 1.2) kΩ/10 cm to 3.9 (± 0.8) kΩ/10 cm. Final conclusion is that among the ways, to improve conductivity for PEDOT coated fibers, applied in this study are best results obtained by multi-layer coating.
2

Patterning of Highly Conductive Conjugated Polymers for Actuator Fabrication

Falk, Daniel January 2015 (has links)
Trilayer polypyrrole microactuators that can operate in air have previously been developed. They consist of two outer layers ofthe electroactive polymer polypyrrole (PPy) and one inner layer of a porous poly(vinylidene flouride) (PVDF) membranecontaining a liquid electrolyte. The two outer layers of PPy are each connected with gold electrodes and separated by the porousPVDF membrane. This microtool is fabricated by bottom-up microfabrication However, porous PVDF layer is not compatible with bottom upmicrofabrication and highly swollen SPE suffers from gold electrode delamination. Hence, in this MSc project/thesis a novelmethod of flexible electrode fabrication with conducting polymers was developed by soft lithography and drop-on-demandprinting. The gold electrodes were replaced by patterned vapor phase polymerized (VPP) poly(3,4-ethylenedioxythiophene) (PEDOT)electrodes due to its high electrical conductivity and versatile process ability. The replacement of the stiff gold electrodes byflexible and stretchable PEDOT allowed high volume change of the material and motions. The PEDOT electrodes werefabricated by patterning the oxidant iron tosylate using microcontact printing and drop-on-demand printing. Moreover, thePVDF membrane has been replaced by a nitrile butadiene rubber/poly(ethylene oxide) semi-interpenetrating polymer network(IPN) to increase ion conductivity and strechability and hence actuator performance.

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