本篇論文主要探討纖維素奈米晶體(Cellulose Nanocrystals)於電子紡織的應用， 纖維素奈米晶體為一種新穎的綠色材料，具有高機械強度以及獨特的化學以及光學特性，近年來已廣泛的應用在可生物分解的奈米材料或是電子元件。
本篇論文主要分成兩個研究主題，在第一個研究，我們成功開發了一種新型的衣物纖維，具有低成本以及可拋棄式的特性。此纖維的基板為可生物降解的 PDLLA 纖維，且表面附著一層由導電高分子(PEDOT:PSS)以及纖維素奈米晶體所建構的 複合材料，具有感應外部的環境溼度的能力，藉由量測其吸脫附水氣的電阻變化值， 來得知其量測溼度的能力。研究結果發現此新型纖維可達到 2%的準確度以及快速 的反應時間(∼4 秒)，相較於現今商業化的產品，此濕度計不僅具有良好的感測能 力，更達成穿戴式感測的目標。在第二個研究中，利用了傳統電紡絲的功能，來建 構一個奈米纖維紗線(nanofiber yarn)的平台，在特定的製程條件中，導電高分子 材料在電紡絲的過程中會產生自扭(self-twisting)的行為，利用此種自扭的方式， 製作了以奈米纖維組成的紗線，並且探討各項製程參數對紗線結構的影響。

This thesis presents a series of studies in the development of cellulose nanocrystals (CNCs) nanofiber for sensors application.
In the first study, a CNC microfiber was designed and fabricated to demonstrate humidity sensing. The sensor is made of a cellulose composite fiber. The device monitors humidity via a humidity induced electrical impedance change. The compact, efficient design of the fiber makes it ideal to incorporate into textile for applications such as body fluid monitoring and other biometrics. Preliminary result shows that the sensor has a 2% accuracy and 20 to 80% RH range. The electrical impedance changes relative linearly with relative humidity. The sensor also shows a relatively fast response (~4s) compare to current commercial available humidity sensors.
In the second study, a method for fabricating yarn structure made of nanofiber was developed for the application of electronic textile. Concept of electrically self-twisting behavior was proven in the fabricating of PEDOT:PSS/PVA/CNC fiber composite. The two factors including the electric field and conductive treatment were found to be dominant factors for triggering the yarn formation. Moreover, the working parameter and material combination was also discussed.

摘要................................................................................................................................. i
Abstract .......................................................................................................................... ii
Acknowledgements ........................................................................................................ iii
Table of content ............................................................................................................. iv
List of Figures ................................................................................................................ vi
List of Tables .................................................................................................................. x
Chapter 1. Cellulose Nanocrystals (CNCs) ...................................................................... 1
1.1 Introduction ...................................................................................................................... 1
1.2 Background & properties .................................................................................................. 2
1.2.1 Mechanical reinforcement .......................................................................................... 2
1.2.2 Self-assembly liquid crystalline .................................................................................. 3
1.2.3 Biodegradability for electronics .................................................................................. 4
1.3 Motivation for CNCs conductive composite study ............................................................. 5
Chapter 2. Introduction to smart textile ........................................................................... 6
2.1 Introduction ...................................................................................................................... 6
2.2 Background....................................................................................................................... 7
2.2.1 Intrinsic textile sensors ............................................................................................... 7
2.2.2 Introduction to yarn electrospinning ........................................................................... 9
2.2.3 Extrinsic textile sensors ............................................................................................ 11
2.4 Summary ........................................................................................................................ 12
Chapter 3. Design and fabrication of active Cellulose nanocrystal green fibers.............. 13
3.1 General description of the two CNC fiber design ............................................................. 13
3.2 Fabrication of CNC composite-coated microfiber ............................................................ 13
3.2.1 Microfiber design ..................................................................................................... 13
3.2.2 Core biodegradable fiber fabrication......................................................................... 14
3.2.3 Dip-coating of active CNC composite ...................................................................... 23
3.3 Fabrication of CNC nanofiber yarn.................................................................................. 28
3.3.1 Concept of fabrication .............................................................................................. 28
3.3.2 Experiment setup ..................................................................................................... 29
3.3.3 Mechanism of yarn structure formation .................................................................... 30
3.3.4 Exploration of the induced mechanism ..................................................................... 32
3.3.5 Parameter discussion ................................................................................................ 37
Chapter 4. Sensing application of CNC composite microfiber (humidity sensing) ......... 41
4.1 Background..................................................................................................................... 41
4.2 General description of the design..................................................................................... 41
4.2 Sensing mechanism ......................................................................................................... 43
4.3 Characterization of the humidity sensitive microfiber ...................................................... 44
4.3.1 Humidity sensing performance ................................................................................. 44
4.3.2 Hierarchical comparison........................................................................................... 48
Chapter 5. Conclusion & Future direction ..................................................................... 49
5.1 Conclusion ...................................................................................................................... 49
5.2 Future direction ............................................................................................................... 49
5.2.1 Potential application for humidity-sensitive microfiber ............................................. 50
5.2.2 Potential application for conductive nanofiber yarn .................................................. 51
Reference ...................................................................................................................... 52

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