Title Page
Abstract
Contents
Chapter 1. Introduction 19
1.1. Research Background 19
1.1.1. Ionogel 19
1.1.2. Rational Molecular Design of Copolymer Gelator 20
1.1.3. Goals and Outline of This Dissertation 20
Chapter 2. Non-volatile, Ultra-Stretchable Ionic Sensory Platforms 23
2.1. Introduction 23
2.2. Results and Discussion 25
2.2.1. Copolymer Design Strategy for Highly Stretchable Ionogels 25
2.2.2. Electrochemical and Mechanical Characteristics Ionogel 36
2.2.3. Strain Detection Performance of Ionogels 40
2.2.4. Demonstration of 'Ionoskins' for Motion Monitoring Sensor 43
2.3. Conclusion 47
2.4. Experimental Section 48
2.4.1. Materials 48
2.4.2. Synthetic Routes for Copolymers 48
2.4.3. Preparation and Characterization of Ionogel-based Sensors 49
2.4.4. Molecular Characterizations of Fabricated Polymers 49
2.4.5. Viscoelastic and Mechanical Properties of Ionogels 51
2.4.6. Structural Characterizations of Ionogels 51
Chapter 3. Zwitterionic Ionogel with Tunable Ion Mobility for Enhanced Thermoelectric Generator Performance 52
3.1. Introduction 52
3.2. Results and Discussion 55
3.3. Conclusion 85
3.4. Experimental Section 86
3.4.1. Materials 86
3.4.2. Zwitterionic Polymer Fabrication 86
3.4.3. Ionogel Preparation 87
3.4.4. Self-healing Electrode and Ionic TEG Fabrication 87
3.4.5. Characterization 88
Chapter 4. Ion-Cluster-Mediated Ultrafast Self-Healable Ionoconductors for Reconfigurable Electronics 91
4.1. Introduction 91
4.2. Results and Discussion 93
4.2.1. Rational Design for Ultrafast Self-healable Ionoconductors 93
4.2.2. Unveiling the Self-healing Mechanism 103
4.2.3. Self-healing Performance on Electrical Properties and Application in Ionoskin Sensors 116
4.2.4. User-reconfigurable AC Electroluminescent Displays 121
4.3. Conclusion 126
4.4. Experimental Section 129
4.4.1. Materials 129
4.4.2. Chracterization 130
4.4.3. Synthesis of Copolymers 131
4.4.4. Preparation of Film Type Ionoconductors 133
4.4.5. Fabrication and Characterization of Strain Sensors 133
4.4.6. Fabrication and Characterization of Reconfigurable ACEDs and Supercapacitors 133
Chapter 5. Conclusion 135
References 138
Abstract in Korean 145
Table 2.1. Molecular characteristics of synthetic polymers employed in this work. 28
Table 3.1. Thermoelectrical performance of the p-polymer and n-polymer TEGs. 82
Table 4.1. Molecular characterizations of polymers prepared in this work. 95
Table 4.2. Vogel-Fulcher-Tammann (VFT) temperature fitting parameters of temperature dependence of the α₂ process. 114
Figure 2.1. (a) Synthetic route for PMMA-r-PBAs. (b) SEC chromatograms of prepared polymers employed in this study. 29
Figure 2.2. ¹H NMR spectrum of (a) PMMA, (b) 88-PMMA-r-PBA. (c) 57-PMMA-r-PBA, and (d) 34-PMMA-r-PBA. 30
Figure 2.3. (a) ¹H NMR spectrum of (a) 17-PMMA-r-PBA. (b) PBA, (c) PEMA and (d) 89-PMMA-r-PS. 30
Figure 2.4. Isothermal frequency sweeps of dynamic storage (G') and loss (G") moduli at a strain amplitude of 0.05 for ionogels containing 40 wt% of (a) PMMA,... 31
Figure 2.5. Optical microscopic images of (a) PMMA, (b) 88-PMMA-r-PBA, and (c) PBA based ionogels. 32
Figure 2.6. (a) SAXS profiles of ionogels based on homo PMMA and 88-PMMA-r-PBA. The lines represent fit to the unified model. (b) Stress-strain curves for... 33
Figure 2.7. DSC thermograms of 89-PMMA-r-PS, PMMA, 88-PMMA-r-PBA, PEMA and PBA obtained during the second run at a heating rate of 10 ℃/min. 34
Figure 2.8. Photographs of the PEMA-based ionogel at different applied strains. 34
Figure 2.9. Schematic illustration of the stretchable ionogels in this work before (left) and after stretching (right). 35
Figure 2.10. Stress-strain curves of PMMA-r-PBA-based ionogels with various mole fractions of PMMA in 40 wt% of PMMA-r-PBA copolymers. 35
Figure 2.11. (a) Frequency dependence of the impedance (Z') and (b) stress-strain curves of ionogels based on 88-PMMA-r-PBA and [EMI][TFSI] at three different... 38
Figure 2.12. Stress-strain curves during a cyclic stretching/releasing process at different strains (i.e., 100, 200, 300, and 600 %). 39
Figure 2.13. (a) Changes in stress-strain curves of 40 wt% 89-PMMA-r-PS based ionogel at a 100 % strain after various numbers of stretching/releasing cycles. (b)... 39
Figure 2.14. (a) Photographs of circuits consisting of 88-PMMA-r-PBA based ionogel and LED, in which the change in resistance of the gel upon application... 41
Figure 2.15. (a) Resistance changes at various applied strains (lower strain range<10 %). (b) Long-term operation at ε~100 % of the 88-PMMA-r-PBA based gel... 42
Figure 2.16. Transmittance spectrum of 40 wt% of 88-PMMA-r-PBA ionogel with a thickness of 1 mm, in which the transmittance level was higher than... 45
Figure 2.17. (a) Schematic illustration of practical application of ionoskin. The insets display photographs of devices applied to finger, elbow, ankle and knee.... 46
Figure 3.1. Zwitterionic copolymer-based fully self-healable thermoelectric generator. (a) Photographs of the p-polymer and n-polymer TEGs connected in... 59
Figure 3.2. Synthetic routes for (a) n-type and (b) p-type ZI copolymers employed in this work. 60
Figure 3.3. NMR spectra of the synthesized (a) p-type and (b) n-type copolymers. Both contained the same molar fraction of non-ionic parts such as 80 mol% of MMA. 61
Figure 3.4. DSC thermograms of p-type and n-type copolymers. 62
Figure 3.5. FTIR spectra of (a) p-polymer and (b) n-polymer TEGs, depicting significant peak shifting induced by strong interactions between the ZI polymers... 63
Figure 3.6. Temperature dependent FT-IR spectra (peak normalized) of (a) p-polymer TEG and (b) n-polymer TEG. The peak of the C-H symmetric stretching... 64
Figure 3.7. Seebeck coefficients of the n-type ion pairs. The data were extracted from previously reported research. 65
Figure 3.8. Complex viscosity vs. angular frequency of the p-polymer and n-polymer ionogels containing [EMI][DCA]. In this study, the same weight percent... 65
Figure 3.9. Thermoelectric characterization of ZI-based TEG according to the various type of ionic liquid. (a) Si of the p-polymer TEG comprising of...[이미지참조] 66
Figure 3.10. Characterization of LM-based pressure activated self-healing electrode. (a) Photograph of the stretched self-healing electrodes and schematic... 69
Figure 3.11. Optical microscopic images of the activated self-healable electrode. 70
Figure 3.12. (a) Self-healing performance of the LM/WPU/PVA composite at various healing periods and conditions. (b) Strain-stress curve of the pristine... 70
Figure 3.13. Characterization of ZI copolymer ionogels. (a) Segmental relaxation time of the p-polymer and n-polymer ionogels according to the IL concentrations... 74
Figure 3.14. G' and G" as a function of the angular frequency of (a) p-polymerand (b) n-polymer ionogels. The arrows indicate the crossover frequency that... 75
Figure 3.15. Thermoelectric performance characterization before and after self-healing of (a) p- and (b) n-polymer TEGs at 1 K temperature difference. 75
Figure 3.16. Performance of p- and n-polymer TEGs. (a) Schematic illustrationof the p-polymer and n-polymer TEGs operating between the hot and cold... 78
Figure 3.17. Output voltage profiles of (a) p-polymer and (b) n-polymer TEGs in relation to the humidity. 79
Figure 3.18. Humidity dependency of Bode plot on ionogel based TEG. Bode plots showing real (Zre), imaginary impedance (Zim) and relevant charge...[이미지참조] 80
Figure 3.19. Power profiles of (a) p-polymer TEG, (b) n-polymer TEG, and (c) p/n-legged TEGs during the open-circuit discharging process induced by... 81
Figure 3.20. Demonstration of reconfigurable ionic TEG systems. (a) Schematic illustration of the fabrication of the p/n-legged TEGs connected in series. The... 84
Figure 4.1. Synthetic routes for preparing (a) AAHAs and (b) DAHA. 96
Figure 4.2. Schematic illustrations of ionic polymer-based ionoconductor (92-AAHA-IL), in which both hydrogen bonding and ion-cluster formation take place,... 96
Figure 4.3. ¹H NMR spectra of prepared polymers. (a) 100-AAHA, (b) 92-AAHA,(c) 61-AAHA, and (d) 90-DAHA. 97
Figure 4.4. SEC traces of polymers employed in this study. (a) 100-AAHA, 92-AAHA, and 61-AAHA. To prepare the GPC samples, the synthesized AAHAs... 98
Figure 4.5. (a) Time-temperature master curves of G' and G" for 92-AAHA-IL and 90-DAHA-IL. (b) Influence of wt% of [EMI][TFSI] on λₛ of 92-AAHA-IL.... 99
Figure 4.6. Frequency-dependent dynamic storage (filled circle) and loss (open circle) moduli at various temperatures for (a) 92-AAHA-IL and (b) 90-DAHA-IL. 100
Figure 4.7. Changes in segmental relaxation time of 90-DAHA-IL according to the weight fraction of the introduced [EMI][TFSI]. The red dotted-line indicates... 100
Figure 4.8. DSC thermograms of 92-AAHA-IL, 90-DAHA-IL, and 92-AAHA-PC, obtained during the second run at a heating rate of 10 ℃·min⁻¹. 101
Figure 4.9. Snapshots from Supplementary Movie 1 showing the immediate self-healing capability of 92-AAHA-IL. The balloon-shaped 92-AAHA-IL was... 101
Figure 4.10. (a) Stress-strain curves during cyclic stretching/releasing at 800% and (b) corresponding changes in recovery ratio and residual strain. The recovery... 102
Figure 4.11. Tensile stress-strain curves of as-prepared and healed 90-DAHA-IL(5-60 mins) at 25 ℃. 102
Figure 4.12. (a) Schematic illustration of 92-AAHA-PC. (b) Tensile stress-strain curves for self-healing tests of 92-AAHA-PC at 25 ℃, and (c) self-healing... 108
Figure 4.13. (a) Differences in self-healing efficiencies measured with different copolymer hosts. Error bars indicate standard deviation. (b) DSC thermograms... 109
Figure 4.14. (a) Comparison of ¹H NMR spectra for 92-AAHA, 92-AAHA-IL, and [EMI][TFSI], in which 92-AAHA-IL contained 30 wt% [EMI][TFSI].... 110
Figure 4.15. ¹H NMR spectra of [EMI][TFSI] with various 92-AAHA-IL contents. The contents of [EMI][TFSI] were 0 (navy line, neat 90-DAHA), 20, 40, 60, 80,... 111
Figure 4.16. (a) Comparison of ¹H NMR spectra of 90-DAHA, 90-DAHA-IL, and [EMI][TFSI]. 90-DAHA-IL contained 30 wt% [EMI][TFSI]. (b) ¹⁹F NMR... 112
Figure 4.17. (a) Angular frequency dependence of dielectric permittivity ε'(ω) of 92-AAHA-IL at 283 K and corresponding static dielectric constant εₛ(red... 113
Figure 4.18. Temperature dependence of ionic conductivity for 92-AAHA-IL and 90-DAHA-IL. 114
Figure 4.19. Time-dependent self-healing efficiency of 92-AAHA-IL with selectively varied (a) cations and (b) anions of the ionic liquid. (c) Plots of molar... 115
Figure 4.20. Mechanical/electrical self-healing of ionoconductors and applications in area-adjustable ionoskins. (a) Cyclic stability tests of 92-AAHA-... 119
Figure 4.21. Self-healing of electrical properties of 92-AAHA-IL film. The flowing current was turned off when the film was cut in half and was recovered... 120
Figure 4.22. (a) Relative resistance variations (ΔR/R₀) under applied strains up to 700% (inset: relative resistance changes at 10, 20, 40, and 60% strains). (b)... 120
Figure 4.23. Reconfigurable AC electroluminescent displays (ACEDs). (a) Schematic illustrations and photographs of the cutting/healing process of an... 123
Figure 4.24. (a) Schematic diagram (left) of ACED and capacitance variations (right) of each component (EL layer and 92-AAHA-IL-based ionoconductor). To... 124
Figure 4.25. (a) Luminance vs. voltage characteristics and (b) CIE color coordinates of blue- and green-emitting ACED as a function of AC voltage at a... 125
Figure 4.26. Successful self-healing of 92-AAHA-IL in extreme environments: (a) sub-zero temperature and (b) underwater environment. (c) TGA thermogram... 127
Figure 4.27. (a) Schematic illustration of self-healable ionoconductor-based electrical double layer capacitor (EDLC). The inset displays a photograph of the... 128