• Cavaillé, J.-Y.
• Masenelli-Varlot, K.
• Seveyrat, L.
• Lebrun, L.
• Jomaa, M. H.

Abstract

Some polyurethanes have demonstrated their ability to convert electrical energy into mechanical energy and vice versa. Furthermore, these materials are lightweight, very flexible, presenting low manufacturing costs, and can be readily molded into any desirable shape. It has been recently pointed out that this strong electrostriction results mainly from the phase separation into domains rich in Hard Segments (HS) with high dielectric constant and domains rich in Soft Segments (SS), and weak dielectric constant. This, in turn leads to heterogeneities of both elastic constants and dielectric constants and to electric field gradients, which shrinks the soft domains and compresses the whole material. It is thus important to optimize the polyurethane microstructure, which mainly depends on the polymer composition. In this work, we compare three types of commercial PU, namely PU88, for Estane 58888 NAT 021, PU75, for Estane X-4977 NAT 039 and PU60 for Estane ETE60DT3 NAT 022 with different weight fractions of (HS) and (SS): (45%, 55%), (26%, 74%) and (65%, 35%), respectively. In order to select the best PU for its use as actuator or energy harvesting material, a complete analysis of the physical properties (namely electrical, mechanical and electrostrictive) of these 3 pure PUs was performed.

Topics

• impedance spectroscopy
• microstructure
• phase
• dielectric constant
• rubber