Development of Multifunctional Self-healing Composites for Multimodal Sensing Applications : Development of Multifunctional Self-healing Composites for Multimodal Sensing Applications
Development of Multifunctional Self-healing Composites for Multimodal Sensing Applications
- 주제(키워드) Self-healing , Stretchable , Wearable electronics , Sensors , Health & environmental monitoring
- 주제(DDC) 621.042
- 발행기관 아주대학교 일반대학원
- 지도교수 Hyungtak Seo
- 발행년도 2024
- 학위수여년월 2024. 2
- 학위명 박사
- 학과 및 전공 일반대학원 에너지시스템학과
- 실제URI http://www.dcollection.net/handler/ajou/000000033371
- 본문언어 영어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
In recent years, self-healing composites are being investigated with tremendous interest due to their great potential in soft robotics, human-machine interaction, intra-body monitoring, biomedical sectors, healthcare, environmental monitoring, and many other sophisticated fields of applications. Majority of the developments have been cultivated towards specific applications that offer limited self-healability while lacking many other underlying functionalities such as stretchability, flexibility, self-adhesiveness, biocompatibility, etc. In most cases, some external stimuli, such as high temperature, pressure, water intervention is required for the healing mechanism to occur. Very few of them are reported to perform intrinsic self-healing at room temperature, without needing an external stimulus. But they require extremely long heling time, which limits their efficacy in practical applications. In this regard, development of multifunctional composites having intrinsic and rapid self-healability at room temperature could be a breakthrough. Especially, such multifunctional self-healing composites dedicated for each and every sectors are indispensable to meet the criteria of technological challenges for the next-generation’s sustainable, and smart sensing applications. To this purpose, innovation of a set of rapid and intrinsically self-healing multifunctional composites have been introduced in this dissertation. The objective of these new innovations was the advancement of smart sensing applications particularly, focusing on two of the most important fields: 1) wearable electronics and 2) environmental safety. The innovations enclosed in this dissertation have been organized as follows: Chapter 2 reports the development of a cost-effective and multifunctional composite having simultaneous functionalities of electrical conductivity, stretchability, and self-healability. It provides a high stretchability (≥120%), and excellent self-healability at ambient conditions within 5 min, which were obtained through a two-steps sol–gel method using supramolecular polymer, copper microparticles (µCu), and urea crosslinkers. It also exhibits high mechanical (90%), and electrical (100%) healing efficiencies even after repeated damage-healing cycles. Owing to these remarkable multifunctional properties, the developed composite was further utilized to fabricate wearable strain sensor that successfully performed real-time human motion detection. Chapter 3 introduces a novel multifunctional composite developed based on the double network (DN) hybrid polymerization of polyborosiloxane (PBS) and a silicon rubber (commercially called Ecoflex). The developed PBS:Ecoflex hybrid polymer performs as a skin-like substrate that simultaneously possesses rapid self-healing (in 10 s at room temperature), high mechanical strength, stretchability (over 500%), transparency (90% of the visible light), good thermal-chemical stability, ideal electrical insulation, and self-adhesive (skin-attachable) properties. Such a multifunctional skin- mimicking self-healing and stretchable (SHS) substrate is reported for the first time in literature, which has a great potential for numerous biomedical and wearable applications like e-skin. As a proof of concept, a wearable pressure sensor array was developed using our skin-like substrate, which was then successfully attached to the human skin for monitoring the pressure responses. Chapter 4 presents the development of amino functionalized multiwalled carbon nanotubes (NH2- MWCNTs) based self-healing composite. Our developed supramolecular organic polymer was used as the self-healing unit in this composite, whereas successful incorporation of NH2-MWCNTs into the polymer facilitates improved electrical and mechanical performances. To achieve this, we also developed a facile synthesis method for functionalization of MWCNTs with NH2 groups. Thanks to the outstanding performances of our newly developed NH2-MWCNTs based composite, and previously developed skin-like substrate (PBS:Ecoflex), completely SHS wearable strain and temperature sensors were developed. The sensors’ performances justify the potential of our developed composite for healthcare and human monitoring due to its remarkable performance towards multimodal stimulus sensing. Chapter 5 presents the innovation of H2 sensing tape using a combination of our developed Pd-WO3 chemochromic nanocomposites (NCs) and PBS: Ecoflex hybrid polymer. The developed tape is self- healing, stretchable, and self-adhesive that can be easily wrapped around pipes, flanges, or any other substances for robust H2 leakage detections with naked eye. Thanks to the excellent mechanical properties, the tape also offers reusability that adds on a great economic impact in the H2 sensing technology. The significant contributions of this dissertation include innovation of multifunctional self-healing composites, followed by the experimental validation of high-performing, and proof-of-concept demonstrations. Composites developed and utilized for physical (strain, pressure, and temperature) sensors outperform for each dedicated application, justifying their great potential in wearable electronics, especially for human motion detection and health monitoring. The composite developed for chemical i.e., H2 gas sensing, on the other hand, exhibits proven performances in real environment H2 leakage detections, demonstrating its efficacy in robust environmental safety monitoring. Overall, the significant contributions of this dissertation opened a promising direction for smart sensing applications and will also put a paradigm shift in self-healing and stretchable multifunctional composite research, which is highly desirable for next generation’s sustainable technologies.
more목차
Chapter 1. Introduction 1
1.1. Background 1
1.1.1. Self-healing Composites for Wearable Sensing 1
1.1.2. Self-healing Composites for Environmental Safety Monitoring 2
1.2. Motivation 3
1.2.1. Natural Structure and Healing Mechanism of Human Skin 3
1.2.2. Human-inspired Smart Sensing 4
1.3. Literature Review & Research Scope 5
1.3.1. Multifunctional Self-healing Composites 6
1.3.2. Self-healing Mechanisms 7
1.3.2.1. Extrinsic Self-healing 8
1.3.2.2. Intrinsic Self-healing 8
1.3.3. Applications of Self-healing Composites 9
1.4. Thesis Organization 9
Chapter 2. Self-healing Strain Sensor for Human Motion Detection 12
2.1. Introduction 12
2.2. Experimental Section 14
2.2.1. Materials and reagents 14
2.2.2. Formation of supramolecular oligomer 14
2.2.3. Synthesis of self-healing electroconductive (SHE) composite 14
2.2.4. Fabrication of wearable strain sensor 15
2.2.5. Characterization and measurements 15
2.3. Results and Discussion 16
2.3.1. Molecular design and self-healing mechanism of SHE composite 16
2.3.2. Material characterization 18
2.3.3. Self-healing demonstration 20
2.3.4. Electrical properties of self-healing composite 23
2.3.5. Mechanical and electromechanical properties 26
2.3.6. Self-healing electroconductive composite as wearable strain sensor 28
2.3.7. Reliability and durability 30
2.4. Summary 31
Chapter 3. Skin-like Self-healing Substrate for Wearable Electronics 32
3.1. Introduction 32
3.2. Experimental Section 35
3.2.1. Materials and reagents 35
3.2.2. Synthesis of PBS 35
3.2.3. Synthesis of Ecoflex 36
3.2.4. Synthesis of PBS: Ecoflex substrates 36
3.2.5. AgNW electrode deposition by spray-coating 36
3.2.6. AgNW/PEDOT: PSS electrode deposition by spin-coating 36
3.2.7. Ni electrode deposition by RF sputtering 37
3.2.8. Fabrication of 4×4 Ni electrode array 37
3.2.9. Fabrication of wearable pressure sensor array 37
3.2.10. Fabrication and implantation of graphene-based resistive sensor 37
3.2.11. Characterization and measurements 38
3.3. Results and Discussion 38
3.3.1. Molecular design and self-healing mechanism 38
3.3.2. Skin-like mechanical properties and self-healability 42
3.3.3. Material, chemical, and optical properties 47
3.3.4. Self-Adhesive properties 50
3.3.5. Electrical properties 53
3.3.6. Proof of concept 55
3.4. Summary 57
Chapter 4. NH2 Functionalized MWCNTs Based Self-healing Smart Sensing 59
4.1. Introduction 59
4.2. Experimental Section 60
4.2.1. Materials and reagents 60
4.2.2. Amino (NH2) functionalization of multiwalled carbon nanotubes (MWCNTs) 61
4.2.3. Synthesis of NH2-MWCNT based SHS conductive composite 61
4.2.4. Fabrication of self-healing and stretchable (SHS) strain sensor 61
4.2.5. Fabrication of self-healing and stretchable (SHS) temperature sensor 62
4.2.6. Characterization and measurements 62
4.3. Results and Discussion 63
4.3.1. Molecular and structural characterization 63
4.3.2. Mechanical characterization and self-healing 68
4.3.3. Electrical characterization 70
4.3.4. Demonstration of multimodal SHS sensing 72
4.3.4.1. Performance of SHS strain sensor 72
4.3.4.2. Performance of SHS temperature sensor 75
4.4. Summary 77
Chapter 5. Self-healing H2 Sensing tape for Robust Environmental Monitoring 78
5.1. Introduction 78
5.2. Experimental Section 79
5.2.1. Materials and reagents 79
5.2.2. Synthesis of SHS H2 sensing polymer composite 80
5.2.3. Preparation of SHS H2 sensing tape 80
5.2.4. Characterization and measurements 81
5.3. Results and Discussion 82
5.3.1. Structural and physical properties 82
5.3.2. Mechanical and self-healing performances 84
5.3.3. Self-adhesive properties of SHS H2 sensing tape 89
5.3.4. Chemochromic sensing performances of SHS H2 sensing tape 91
5.3.5. Reliability test 94
5.4. Summary 96
Chapter 6. Conclusion 97
6.1. Summary 97
6.2. Limitations 98
6.3. Future Works 99
6.3.1. Improvement of SHS H2 sensor and other sensors 99
6.3.2. Self-healing soft robotics 100
Appendix A. Supplementary Information of Chapter 2 102
Appendix B. Supplementary Information of Chapter 3 110
Appendix C. Supplementary Information of Chapter 4 121
Appendix D. Chemochromic Hydrogen Sensing 125
Appendix E. Supplementary Information of Appendix D and Chapter 5 145
Bibliography 151
