A study on the conductive nanoparticle-based photocurable composite film for sensing applications = 전도성 나노입자 기반 광경화 복합재 필름 제조 및 이를 이용한 센싱 소자에 관한 연구

다국어 초록 (Multilingual Abstract)

In this study, conductive composite films were fabricated using a UV laser-sintering process and evaluated for application in flexible and wearable strain sensors. By tuning the laser power, residence time, nanoparticle loading ratio, and scan interval, the electrical and mechanical properties of the films were effectively controlled. Three sensing modes—Ohmic, mechanical crack, and opened crack—exhibited distinct ΔR/R responses, and sensors embedded in PDMS showed stable performance under repeated deformation. Patterned structures such as multi-line and grid geometries demonstrated different levels of sensitivity and signal stability depending on their configuration. A wearable sensor attached to the forearm successfully detected muscle movements during hand motions. Furthermore, a multilayer structure with three stacked conductive layers was fabricated, confirming the scalability of the proposed process.

국문 초록 (Abstract)

본 연구에서는 UV 레이저 소결 공정을 이용해 전도성 복합 박막을 제작하고, 이를 유연 및 웨어러블 변형 센서로 적용하기 위한 특성을 평가하였다. 레이저 파워, 조사시간, 나노입자 함량비, 스캔 간격을 조절함으로써 박막의 전기적 및 기계적 성능을 효과적으로 제어할 수 있었다. 오믹, 기계적 크랙, 오픈 크랙의 세 가지 센싱 모드에서 서로 다른 ΔR/R 특성이 나타났으며, PDMS에 삽입된 센서는 반복 변형에서도 안정적인 응답을 유지하였다. 멀티라인과 그리드 패턴 센서는 구조 차이에 따라 감도와 신호 안정성이 달라졌고, 팔뚝에 부착한 웨어러블 센서는 손 동작에 따른 근육 움직임을 성공적으로 감지하였다. 또한 세 개의 전도층을 적층한 멀티레이어 구조를 제작하여 공정의 확장 가능성도 확인하였다.

목차 (Table of Contents)

• Chapter I Introduction 1
• 1.1 Flexible and wearable electronic sensors 1
• 1.2 Fabrication techniques for flexible sensors 2
• 1.3 Objectives 3
• Chapter II Laser sintering system and fabrication process 4
• 2.1 Materials 4
• 2.2 UV laser sintering system 5
• 2.3 Fabrication of conductive composite films 6
• 2.3.1 Fabrication process of composite films 6
• 2.3.2 Laser sintering parameters for composite films 8
• 2.3.3 Composite films with various geometries 12
• Chapter III Characterization of laser-sintered composite films 14
• 3.1 Microstructural characteristics 14
• 3.2 Thickness evaluation 17
• 3.3 Electrical properties 20
• 3.4 Mechanical and electromechanical properties 23
• 3.4.1 Stressstrain characteristics 25
• 3.4.2 ΔR/R responses under tensile load 31
• Chapter IV Composite films for sensing applications 36
• 4.1 Strain-sensing behavior of composite films 36
• 4.1.1 Ohmic mode 38
• 4.1.2 Mechanical crack mode 39
• 4.1.3 Opened crack mode 41
• 4.2 Durability and cyclic performance 43
• 4.3 Sensing performance of films with extended geometries 46
• 4.4 Wearable sensor for forearm muscle-movement detection 51
• Chapter V Multi-layer structure 54
• 5.1 Multi-layer fabrication 54
• 5.2 Demonstration of the multi-layer structure 56
• Chapter VI Discussion and conclusion 57
• [Reference list] 58