Deformation and viscoelastic behavior of polymer gels in electric fields

Abstract

Smart polymer gels actively change their size, structure, or viscoelastic properties in response to external signals. The stimuli-responsive properties, indicating a kind of intelligence offer the possibility of new gel-based technology. This paper presents two types of electromechanical behavior that take place in smart polymer gels. One is an anisotropic swelling of polyelectrolyte gels in a salt solution under the influence of electric fields. The swelling deformation produces bending of rectangular gels with large deflection. The swelling or bending is found to be induced by an increase in osmotic pressure due to ion's drifts in electric fields. The other concerns composite gels whose modulus of elasticity can vary in electric fields. The driving force causing varying elastic modulus in electric fields is the interaction between polarized particles similar to electrorheological (ER) effect and discussed experimentally as well as theoretically.