<title>Optically driven polymer actuator using reversible photo-induced phase-transition phenomena</title>

Abstract

The authors propose a new optically-driven actuator system which utilizes 'photo-induced phase-transition' (PIPT) phenomena. This system is expected to be useful for micromechanical systems, since it provides wireless energy supply by light. The concept and the material properties are reported. PIPT phenomena have been recently reported to occur in various materials. These materials show bi-stability on their material phase such as structure, optical properties, magnetic properties, etc. The phase of the material is changed by irradiation of light with fixed wavelength, as well as by temperature or external fields. In this report, a kind of polydiacetylene (PDA) substituted with alkyl-urethane is investigated. This material is known to show reversible PIPT around 125 degrees Celsius between 'blue' phase and 'red' phase. The authors measured the induced macroscopic elongation of PDA crystal using a laser-focus displacement meter. For the first step, the phase of the sample was controlled by thermal phase-transition hysteresis. The induced strains due to the phase transition were measured to be highly anisotropic: 2%, 0.03%, and 0.9% at 125 degrees Celsius for a-, b-, and c-axes, respectively. These values are larger than that of piezoelectric or thermal-expansion materials that are conventionally used for microactuators. Thus this material is expected to be used for mechanical actuators, which are driven not only thermally, but also optically.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.