Title Page
Contents
요약 7
Abstract 8
Chapter 1. Introduction 11
Chapter 2. Background 14
2.1. Flexible Substrate 14
2.1.1. Cellulose 14
2.1.2. Methylcellulose 15
2.2. Conductivity Material 15
2.2.1. Carbon Nanotube (CNT) 15
2.2.2. Multi-Wall Carbon Nanotube (MWCNT) 16
2.2.3. A Study on the Application of CNT and Cellulose 16
Chapter 3. Experimental Section 20
3.1. Materials and preparation 20
3.2. Characterization 20
3.3. Circuit Fabrication 21
3.4. FPCB operation 21
Chapter 4. Result & Discussion 22
4.1. The fabrication process of transparent MC FPCB 22
4.2. Characteristics of MC substrate 23
4.3. Stress–strain curves of the MC substrate 23
4.4. Dielectric constant of MC substrate 24
4.5. Mechanical test for MC FPCB 25
4.6. LED circuits 26
4.7. Single layer 5 x 5 LED display 27
4.8. Wearable touch sensor array panel 27
4.9. Via holes for double layer MC substrates 28
4.10. Double layer 5 x 5 LED display 28
4.11. Communications for the cellulose devices 29
Conclusion 49
Reference 50
Fig. 2.1. Chemical Structure of Cellulose 18
Fig. 2.2. Chemical Structure of Methylcellulose 18
Fig. 2.3. Image of Multi-Wall Carbon Nanotube (MWCNT) 19
Fig. 2.4. Cellulose-based Flexible Energy Storage System 19
Fig. 4.1. (a) Fabrication process for the MC substrates. (b) Image of the transparent MC substrate. (c) SEM image of the MC substrate. (d) Fabrication process for the Ag/CNT... 30
Fig. 4.2. (a) XRD pattern and (b) FTIR spectrum of the MC substrate. 31
Fig. 4.3. (a) Stress–strain curves and (b) resistance-ratio–strain curves of the MC substrates with various thicknesses. 32
Fig. 4.4. (a) Capacitance measurement procedure. (b) Graph of capacitance and dielectric constant with respect to the MC substrate thickness. 33
Fig. 4.5. (a) Schematic of the Ag/CNT composite on the MC substrate. (b) SEM images of the Ag/CNT composites on the MC substrate. (c) I–V curves of Ag/CNT composite circuits. (d–e)... 34
Fig. 4.6. (a) Fabrication process of the LED circuit. (b) Images of the LED circuit. (c–f) Optical microscopy images of the LED circuits. (g–j) SEM images of the LED circuits. 35
Fig. 4.7. (a) Fabrication process of the 5 x 5 LED circuit. (b) Image of the 5 x 5 LED circuit. (c–d) Images of the operation of the LED circuit. 36
Fig. 4.8. (a) Diagram of the double layer touch sensor panel. (b) Communication process between the sensor, Arduino board, and MFC display. (c–d) Images of the touch operation and display. 37
Fig. 4.9. (a) Diagram of a double layer LED circuit with a via hole. (b) Image of the circuit with the via hole. (c–d) SEM images and (e–f) Magnify SEM images of... 38
Fig. 4.10. (a) Diagram and (b) image of the top and bottom substrates. (c) the assembled layers with LEDs. (d) Diagram and image of the via hole. (e) the communication process between the... 39
Fig. 4.11. (a) the communication process between the double layer circuits, MFC program, and Arduino boards. (b–e) Images of the operation of the communication system. 40
Fig. 4.S1. Optical images of MC with other solvents by sonicator (a) DMSO, (b) EtOH and (c) IPA. 41
Fig. 4.S2. Total thickness of MC substrate fabricated by diverse volume of solutions with evaporation process. 42
Fig. 4.S3. Optical images of Ag/CNT composites by four difference CNT concentration (a) 0wt. %, (b) 4.3 wt. %, (c) 9.9 wt. %, and (d) 16.7 wt. % 43
Fig. 4.S4. (a) Optical images and (b) screen capture images of customized MFC program for control the FPCB. 44
Fig. 4.S5. Optical images of capacitance measurement in 5x5 MC touch panel when (a) nontouch, (b) touch with hands. 45
Fig. 4.S6. Text images of the Arduino coding contents used in the 5x5 touchpanel. 46
Fig. 4.S7. (a-f) SEM images of diverse multi-layer in MC substrate with Ag/CNT composite. 47
Fig. 4.S8. Text images of the MFC program coding contents used in the 5x5 LED circuit and MC touch panel. 48