Title Page
Abstract
Contents
Chapter 1. Improved Performance and Reliability of Single-Layer Electrochromic Systems Improved Performance and Reliability Using High-Voltage Pulse-Assisted Operation 20
1.1. Introduction 20
1.2. Experimental 22
1.2.1. Materials 22
1.2.2. Fabrication of SL-ECDs 23
1.2.3. SL-ECD characterizations 23
1.3. Results and Discussion 24
1.4. Conclusions 37
1.5. References 38
Chapter 2. Controlling the π-π Interaction of Copolymer Gelators: Efficient Molecular Design of Highly Stretchable and Tough Ionogels for Wearable Ionotronics 43
2.1. Introduction 43
2.2. Experimental 45
2.2.1. Materials 45
2.2.2. Synthesis of Copolymers 46
2.2.3. Analysis of Copolymers 47
2.2.4. Strain Sensor Fabrication 48
2.2.5. Fabrication of Pressure Sensor 49
2.2.6. Fabrication of ACED 49
2.2.7. Device Characterization 50
2.3. Results and Discussion 50
2.4. Conclusions 73
2.5. References 74
국문초록 78
Table 2.1. Molecular characteristics of the copolymer types[내용없음] 9
Table 2.2. Comparison of several advanced hydrogel and ionogel systems.[내용없음] 9
Table 2.3. Results of mechanical stabbing test.[내용없음] 9
Figure 1.1. Comparison Conceptual illustrations of the operation of SL-ECDs under two different conditions: a basic DC voltage (conventional) and a... 25
Figure 1.2. Cyclic voltammogram of the EC gel containing dmFc and EtV²⁺ (scan rate of 20 mV s⁻¹). The working, reference, and counter electrodes were a Pt disk,... 26
Figure 1.3. Fundamental three parameters of the programmed voltage profiles for high-voltage pulses: frequency, pulse amplitude (namely, peak-to-peak... 27
Figure 1.4. Bode plot of the EC gel including 90 wt% [EMI][TFSI], 10wt% of PS-r-PMMA, equimolar (80 mM) EtV(PF₆)₂, and dmFc. 27
Figure 1.5. (a) The programmed input voltage Profiles comprising of DC -0.7 V and high-voltage pulses, in which the frequency with the fixed frequency of 1... 28
Figure 1.6. Nyquist plot of the EC gel containing [EMI][TFSI], PS-r-PMMA, dmFc, and EtV(PF₆)₂. 29
Figure 1.7. UV-vis absorption spectra at two programmed voltage waves: 1.2 Vₚₚ and 1.4 Vₚₚ pulses at 1 kHz and 10% duty ratio. The device degradation was... 30
Figure 1.8. (a) Profiles of the programmed voltage at various duty ratios, with a fixed amplitude of the high-voltage pulse at 1.2 Vₚₚ. (b) Time-dependent... 30
Figure 1.9. Transient transmittance profiles of the SL-ECD at various Vₚₚ under maintaining constant duty ratios: (a) 10, (b) 50, and (c) 90%. (d) Comparison... 32
Figure 1.10. UV-vis absorption spectra and schematic illustration of the symmetric SL-ECD operation (a) when negative biases were applied to the... 33
Figure 1.11. (a) UV-vis absorption spectra of the SL-ECDs under various bleaching conditions. The use of DC +0.7 V resulted in coloration at the counter... 34
Figure 1.12. (a) Programmed input voltage profiles on the optimized conditions for coloration and bleaching. (b) Time-dependent transmittance change and (c)... 35
Figure 1.13. Transmittance change of the enlarged (2 cm×3 cm) SL-ECD under the optimized pulse voltage conditions of coloration and bleaching. 37
Figure 1.14. Long-term stability test of SL-ECD with DC conditions (-1.9 V for coloration and +0.7 V for bleaching) for 10,000 s. 37
Figure 2.1. Schematic illustrations of the molecular design strategy for the copolymers utilized to achieve highly stretchable and tough ionogels. (a) The... 52
Figure 2.2. The procedures and conditions for the synthesis of (a) PS-r-PEMA, (b) PMS-r-PEMA, and (c) PtBS-r-PEMA through RAFT polymerization. A... 53
Figure 2.3. Simulated molecular structures and anticipated distance between phenyl ring sites of (a) PS, (b) PMS, and (c) PtBS using Avogadro 1.2.0 software. 53
Figure 2.4. (a) X-ray diffraction patterns for PS, PMS, and PtBS films. (b) DSC thermograms analysis of the three synthetic copolymers. 54
Figure 2.5. ¹H NMR spectra of PS derivative copolymers. (a) PS-r-PEMA consisting of 74 mol% of EMA and 26 mol% of styrene. (b) PMS-r-PEMA... 54
Figure 2.6. (a) Schematic of interactions betwixt [EMI][TFSI] and PEMA. (b) Alterations in the ¹H NMR peak of [EMI][TFSI] in relation to the polymer... 56
Figure 2.7. Photographs of the PtBS gel dyed in blue, depicting (a) its storage at 100 ℃ for 1 h and (b) its application of 10 N pressure. Commercial blue-dye was... 56
Figure 2.8. Digital photographs of the results of (a) the volatility test at room temperature and (b) freezing test at -10 ℃ using PtBS gel and poly(vinyl alcohol)... 57
Figure 2.9. (a) Bode plot of the ionogels containing a copolymer (PS-r-PEMA, PMS-r-PEMA, or PtBS-r-PEMA) and the IL ([EMI][TFSI]) at a weight ratio of... 57
Figure 2.10. Mechanical characterizations of the three ionogels based on the synthesized PS derivative copolymers. (a) Frequency-dependent G' and G" at... 61
Figure 2.11. Characterization of PEMA homopolymer and PEMA gel. (a) SEC chromatograms of PEMA homopolymer. (b) Isothermal dynamic storage (G') and... 62
Figure 2.12. Tensile stress-strain curves of the PtBS gel at different applied strains. 62
Figure 2.13. Demonstration of the tough PtBS gel as a layer for absorbing impact. (a) Schematic representation of the simple process. (b) Images captured... 63
Figure 2.14. Falling-ball impact test with the red-dyed PtBS gel for better monitoring the test results. (a) Digital photograph of the custom ball impact test... 63
Figure 2.15. Application of the PtBS gel -based strain sensor. (a) Relative resistance changes(△R/R₀) at various strains. The inserted images present the variations in... 65
Figure 2.16. Sensing performances of the PtBS gelas as a strain sensor for monitoring human motions. Performance of the motion-detecting sensor affixed... 66
Figure 2.17. Pressure sensory performance of the PtBS gel. (a) Photograph of the skin-type pressure sensor. (b) Frequency-dependent various capacitances... 68
Figure 2.18. Frequency-dependent capacitances of (a) Real part (C'(w)) and (b) imaginary part (C"(w)) before and after compression (frequency range of 10⁻¹ to... 69
Figure 2.19. EL performance of ACEDs incorporating the PtBS gel as a n ionic electrode. (a) Schematic representation of the flexible ACED andit... 71
Figure 2.20. Capacitance changes of the ionogels and blue, green, and orange EL layers as functions of frequency. 72
Figure 2.21. (a) Optical photographs of green colored ACED and (b) changes in luminance during successive stretching/releasing cycles. 72
Figure 2.22. Images showing the operation of the ACEDs made with diverse colors of EL materials affixed to a human hand. 73