ABSTRACT
Several classes of polymeric materials exhibit long-range orientational order that can be strongly affected by electric and/or magnetic fields. These include polymeric liquid crystals, microphase-separated block copolymers with certain symmetries, and ferroelectric polymers. There are many excellent books and review articles on these materials and the influence of applied fields on their order. With the goal of providing something unique to this body of literature, I will discuss electric and magnetic field interactions with these materials, with an emphasis on discerning commonalities and distinctions between the various materials and their responses to applied fields. The guiding philosophy is that it is profitable to elucidate common features and analogies in what are superficially rather disparate systems. First, electric and magnetic field interactions with small-molecule and polymeric liquid crystals are reviewed. Next, the influence of an electric field on microphase-separated block copolymers is discussed. The final subject is electric field poling of the ferroelectric polymer poly(vinylidene fluoride). All of these materials have important industrial applications. Polymeric liquid crystals are used for precision molding because of their flow properties and low thermal expansion coefficient (along one direction). They are used to fabricate high-strength, high-modulus materials. Liquid crystal elastomers are of interest for their piezoelectric properties or coupling between liquid crystalline order and mechanical strain. Liquid crystal polymers may also have electro-optic applications and be used in nonlinear optical materials. Block copolymers are used primarily as thermoplastic elastomers and compatibilizers in polymer blends and in adhesives. Alignment using electric fields offers possibilities for new applications. The ferroelectric polymer poly(vinylidene fluoride) is used as a piezoelectric or pyroelectric transducer in a wide variety of applications because of its processibility and mechanical properties. For all of these
materials, an understanding of the interaction between the orientational order and electric or magnetic fields is important for processing or potential applications, or for determining important characteristics of the material.
