Textile Actuator Fibres: Investigation in materials and methods for coiled polymer fibre muscles
Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
This thesis contains an investigation in materials and methods for coiled polymer muscles where the end application in mind is to be integrated in a textile structure such as an exo-skeleton glove. Previous artificial muscle fibres have proved little success due to performance, cost and scalability. For example, thermally controlled muscles of carbon nanotube material are expensive and muscles from shape memory metal shows difficulty in control. By instead using simple polymer fibres as thermally driven artificial muscles previous problems can be solved. In the present work, different materials such as a semi crystalline poly(vinylidiene fluoride) (PVDF), with two different molecular weights (MW), and a Shape Memory Polymer (SMP) of thermoplastic polyurethane (TPU) have been melt spun into monofilaments, cold drawn and twisted into coils. By changing parame-ters of the melt spinning equipment, fibres of varying thicknesses and with differ-ent molecular orientation were produced. Also a fishing line of fluorocarbons with a known functioning actuation has been used as a comparison. The fibres have been investigated using Differential Scanning Calorimetry (DSC), Dynamic Me-chanical Thermal Analysis (DMTA) and Scanning Electron Microscopy (SEM). The results from this study indicate that fibres used as coiled artificial muscles need to contain a high degree of crystallinity (not amorphous), be cold drawn at high temperature, contain a high degree of orientation and encompass a uniform fibre diameter. In this study the material of a higher MW showed slightly better properties then the material of a lower MW. In PVDF, an interesting relaxation around 50-60°C was identified as relevant for the actuation properties.
Place, publisher, year, edition, pages
Textile actuators, Soft robots, Coiled muscles, PVDF, SMP, Fibre Anisotropy, Thermal actuation, α-relaxation
Engineering and Technology
IdentifiersURN: urn:nbn:se:hb:diva-250OAI: oai:DiVA.org:hb-250DiVA: diva2:825778
Subject / course