UC San Diego

Carbon nanotubes (CNT) have been in the forefront of nanotechnology research since their discovery in 1991. Its multifunctional properties are used in diverse applications such as transistors, gaseous storage material and actuator to name a few. In this thesis, actuation in a composite of CNT with Reactive ethylene terpolymer (RET) due to light has been studied and compared with that observed in PDMS-CNT composite. While PDMS-CNT composite shows a reversible stress response under strain and incident light, RET-CNT yields a reversible stress response along with an irreversible stress response not observed in PDMS-CNT composite. Furthermore, the effects of parameters such as light intensity and uniaxial tensile strain have on actuation have been observed through accurate stress response measurements. Assuming melted crystalline domains of RET as the cause of actuation in the composite, change in shear modulus as a function of number density of crystalline domains is calculated. Based on the results, a microscopic model for photomechanical actuation in thermoplastic-CNT composites is discussed.