Title Page
Contents
LIST OF ABBREVIATIONS 13
ABSTRACT 15
Ⅰ. INTRODUCTION 17
Ⅱ. MATERIALS AND METHODS 21
1. Materials 21
2. Preparation of Hydrogels and Silicone Elastomers 22
3. External Stimulus for Shape-programmable Actuation 24
3.1. Light and Heat 24
3.2. pH and Magnetic 30
4. Methods for Shape-Programmable Actuation 34
4.1. Solvent Selection for the Metal Nanoparticles Embedded 34
4.2. Fabrication 36
4.3. Experimental Setup 41
Ⅲ. RESULTS 43
1. Characterization of Shape-programmable Soft Robots 43
1.1. Light-responsive Soft Robot 43
1.2. pH-responsive Soft Robot 62
2. Applications 74
2.1. Wavelength-selective Multi-shape Programmable Soft Robot 74
2.2. pH-responsive Soft Robot for Targeted Drug Delivery 86
Ⅳ. DISCUSSION 91
1. Future Challenges of Utilization of Light 91
2. Future Challenges of Utilization of pH 92
Ⅴ. CONCLUSION 94
Ⅵ. REFERENCES 96
ABSTRACT IN KOREAN 103
Table 1. Comparison of numerical values for silicone elastomers 60
Figure 1. Light-responsive shape-programmable soft robot 26
Figure 2. Design of wavelength-selective multi-shape programmable silicone/hydrogel soft robot 29
Figure 3. Design of silicone/hydrogel soft robot for targeted drug delivery 31
Figure 4. pH-responsive drug delivery system 33
Figure 5. Solvent selection for metal nanoparticles embedment in silicone elastomer 35
Figure 6. Fabrication process of light-responsive silicone/hydrogel bilayer 39
Figure 7. Fabrication process of 3D printed silicone/hydrogel drug delivery soft robot 40
Figure 8. Experimental setup 42
Figure 9. Rheological characterization of pNIPAM hydrogel and silicone elastomers 44
Figure 10. Printability of silicone elastomers. 47
Figure 11. Optimal selection of bilayer materials 50
Figure 12. Absorption spectrums and optical photographs 52
Figure 13. Photothermal characterization of the light-responsive soft actuator 55
Figure 14. Strain-stress curves of silicone elastomers 60
Figure 15. Controlling the bending morphology via utilizing different silicone elastomers 61
Figure 16. Rheological characterization of ionic hydrogel and Ecoflex 63
Figure 17. Characterization of pH- and temperature-responsive hydrogel 67
Figure 18. Synthesis process of Ecoflex-Fe₂O₃ layer 70
Figure 19. Bidirectional bending behaviors of silicone/hydrogel bilayer as a function of time 71
Figure 20. Drug-loaded hydrogel and dye diffusion from hydrogel 73
Figure 21. Wavelength-selective actuation of a simple actuator 76
Figure 22. Actuation by switching LED irradiated to silver and gold NPs 78
Figure 23. Repeatability test of the wavelength-selective soft actuator 80
Figure 24. Fabrication process of a wavelength-selective multi-shape programmable soft robot 82
Figure 25. 4 different unique states of a wavelength-selective soft robot 85
Figure 26. Details about the fabrication of a soft robot for targeted drug delivery 87
Figure 27. Magnetic guidance and actuation of a soft robot 89