A Polymer-Based Micro Thermal Actuator For Micromanipulations In Aqueous Environment

The development of a novel polymer-based thermal actuator is presented in this paper. It is a trimorph structure with a platinum metal heater encapsulated by Poly-para-xylylene C (parylene C) polymer layers. These polymer layers are used to protect the metal heater and trap heat while the actuator is operating in aqueous environment. We have proved that this thermal actuator can operate in aqueous environment with only 5V maximum input voltage for full deflection (90degrees change of tip direction). The resistance of the heater is around 2kOmega. The dimension of the actuator is 2mmx158mumx0.45mum. Modeling of the trimorph structure together with a method for optimizing its design and the fabrication process for the trimorph structure are discussed. Based on the successful operation of this polymer-based thermal actuator, we are currently developing multi-fingered thermal actuators for cellar grasping and manipulation.