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Author ORCID Identifier
https://orcid.org/0000-0001-8935-9527
AccessType
Open Access Dissertation
Document Type
dissertation
Degree Name
Doctor of Philosophy (PhD)
Degree Program
Polymer Science and Engineering
Year Degree Awarded
2019
Month Degree Awarded
September
First Advisor
Alfred J. Crosby
Second Advisor
Ryan C. Hayward
Third Advisor
Christian D. Santangelo
Subject Categories
Applied Mechanics | Condensed Matter Physics | Dynamics and Dynamical Systems | Polymer and Organic Materials | Polymer Science
Abstract
Recent advances in the field of biomedical and life-sciences are increasingly demanding more life-like actuation with higher degrees of freedom in motion at small scales. Many researchers have developed various solutions to satisfy these emerging requirements. In many cases, new solutions are made possible with the development of novel polymeric actuators. Advances in polymeric actuation not only addressed problems concerning low degree of freedom in motion, large system size, and bio-incompatibility associated with conventional actuators, but also led to the discovery of novel applications, which were previously unattainable with conventional engineered systems. This dissertation focuses on developing novel actuation mechanisms for soft polymeric gel systems with easily adjustable mechanochemical properties and applicability to various environmental conditions. Inspired by stunning examples in nature which exhibit extremely fast motion in a repeatable manner, termed impulsive motion, we have developed polymeric gel actuators applicable for small-scale, self-contained impulsive systems. In particular, we focused on the effect of geometry and the mechanics of surface-mediated stresses on the dynamic shape-change of polymer gel actuators. We found new opportunities from observation of transient deformations which occur during swelling, or deswelling, of asymmetric gels. We described the development of time-dependent three-dimensional deformation mechanism (4D fabrication) by the utilization of transient inhomogeneous swelling state of the asymmetric polymer gel. We discussed the mechanism and the application of the new deformations mechanism for the development of a novel functionality: chemical gradient sensor. In addition, we developed a high-rate and large-strain reversible actuation mechanism for sub-micrometer scale polymeric gel actuators by utilizing balanced effects of two surface-mediated phenomena, surface diffusion and interfacial-tension, and elasticity of soft and small-scale hydrogels. These new findings were harnessed for developing autonomously controlled power amplified polymeric gel devices. Utilizing deswelling induced transient deformation of gel, we developed design principles for generating meta-stable structures and inducing self-regulating transition forces for repeated snap-through buckling transition of polymeric gel devices. In parallel, we deconvoluted the effect of material properties and geometry on dynamic deformations by establishing simulation models and conducting analyses on the performances of actual synthetic systems. The systematic approach will serve to broaden the application spectrum and manufacturing possibilities of polymeric actuator systems.
DOI
https://doi.org/10.7275/15222926
Recommended Citation
Kim, Yongjin, "POLYMERIC IMPULSIVE ACTUATION MECHANISMS: DEVELOPMENT, CHARACTERIZATION, AND MODELING" (2019). Doctoral Dissertations. 1722.
https://doi.org/10.7275/15222926
https://scholarworks.umass.edu/dissertations_2/1722
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
Included in
Applied Mechanics Commons, Condensed Matter Physics Commons, Dynamics and Dynamical Systems Commons, Polymer and Organic Materials Commons, Polymer Science Commons