title: Tailoring Actuation Properties of  Thermoresponsive Hydrogels and  Implementation into Soft Robotic  Applications
creator: Spratte, Tobias
subject: ddc-000
subject: 000 Generalities, Science
subject: ddc-500
subject: 500 Natural sciences and mathematics
subject: ddc-530
subject: 530 Physics
subject: ddc-540
subject: 540 Chemistry and allied sciences
subject: ddc-600
subject: 600 Technology (Applied sciences)
subject: ddc-620
subject: 620 Engineering and allied operations
description: Soft material robotics relies on the development of responsive, soft materials and  requires high standards, with respect to the material properties: High responsivity,  robust mechanical properties, high cycle times, and fast responses are some  examples for these requirements, which are rarely found in such responsive, soft  materials, and thus need to be adjusted by material engineering.  This thesis addresses tailoring the properties of thermoresponsive hydrogels and  implementing these materials into soft robotic applications. Furthermore, a thorough  investigation of material responsivity and mechanical properties is conducted,  which are crucial parameters for the development of soft actuators.  First, a template-assisted fabrication method based on sacrificial zinc oxide templates  is introduced, which yields microporous and highly thermoresponsive hydrogels.  Compared to its conventional bulk counterpart, this material exhibits a  large volume transition and generates considerable stroke forces upon stimulation,  which are crucial requirements for actuator applications. These changes in thermoresponsive  actuation properties result from the increased surface area created  by the microporosity of the hydrogel. Actuation capabilities are demonstrated on  the basis of a soft, thermally controlled gripper.  Based on the previous findings, two-photon 3D laser printing is used to fabricate  responsive hydrogel microactuators with precise control of actuator surfaceto-  volume ratio and to investigate actuation capabilities as a function of actuator  design and fabrication parameters. It turns out that miniaturization of the actuators  and especially the surface-to-volume-ratio have a major impact on responsivity.  In addition, variation of the processing parameters during fabrication is  found to be a facile strategy for tailoring actuator properties, such as stiffness and  responsivity. Moreover, the assembly of individual actuators into microactuator  systems, enables cooperative functions, such as capturing and releasing cargo in a  microfluidic chip upon thermal stimulation.  The micro engineering strategies presented in this work, provide a toolkit for  understanding the science of thermo-actuation and tailoring actuation properties  of responsive hydrogels. Furthermore, methods for developing soft robotic applications  at the microscale using such hydrogels are demonstrated.
date: 2024
type: Dissertation
type: info:eu-repo/semantics/doctoralThesis
type: NonPeerReviewed
format: application/pdf
identifier: https://archiv.ub.uni-heidelberg.de/volltextserverhttps://archiv.ub.uni-heidelberg.de/volltextserver/34624/1/Spratte_Tobias_komplett.pdf
identifier: DOI:10.11588/heidok.00034624
identifier: urn:nbn:de:bsz:16-heidok-346244
identifier:   Spratte, Tobias  (2024) Tailoring Actuation Properties of Thermoresponsive Hydrogels and Implementation into Soft Robotic Applications.  [Dissertation]     
relation: https://archiv.ub.uni-heidelberg.de/volltextserver/34624/
rights: info:eu-repo/semantics/openAccess
rights: http://archiv.ub.uni-heidelberg.de/volltextserver/help/license_urhg.html
language: eng