Abstract
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.