Composite Interfaces, Vol. 15, No. 7–9, pp. 679–685 (2008)  Koninklijke Brill NV, Leiden, 2008. Also available online - www.brill.nl/ci Actuator, sensor and MEMS devices based on regenerated cellulose K. M. SURESHA, SANG YEOL YANG, MIN HEE LEE, JOO-HYUNG KIM and JAEHWAN KIM ∗ Center for EAPap Actuator, Department of Mechanical Engineering, Inha University, 253 Yonghyun-Dong, Nam-Ku, Incheon 402-751, South Korea Received 11 December 2007; accepted 8 March 2008 Abstract—In our early work, cellulose has been discovered as a smart material that can be used as sensors, actuators and smart devices. This newly discovered material is described as electro-active paper (EAPap) and has many advantageous properties: lightweight, flexible, dryness, biodegradable, easy to chemically modify, cheapness and abundance. The actuation principle of cellulose EAPap is based on a combination of piezoelectric and ion-migration effect. This paper reports the fabrication of various micro-patterns and structures, such as rectifying antenna and inter-digital transducer on regenerated cellulose film by adopting a micro-transfer printing technique. Fabrication steps are briefly discussed herein and performance of the actuators was evaluated by means of a tip displacement test. Further, potential application of cellulose as humidity sensor was demonstrated by measuring the impedance change on the inter-digital transducer on cellulose film at different humidity levels. Keywords: Electro-active paper; cellulose; micro-fabrication; micro-electro-mechanical system (MEMS). 1. INTRODUCTION Biopolymers such as cellulose, chitosan and collagen from renewable resources have become increasingly important in the development of advanced materials. Cellulose, a linear 1,4-β -glucan, is the most abundant polymer found in nature. It is produced in a sustainable way and offers many possible uses because of its renewability and biodegradability [1]. It is possible to base an entire line of chemistry on cellulose. Now scientists have made cellulose into all kinds of films, such as films for hemodialysis [2], water resistance [3] and as smart materials [4] (Electro-Active Paper, EAPap), etc. EAPap is made with regenerated ∗ To whom correspondence should be addressed. E-mail: jaehwan@inha.ac.kr