Liquid Crystalline Polymers and Their Nanocomposites

Dear Colleagues,

The liquid crystal (LC) states of polymers were discovered with the discovery of aramids, such as poly(p-phenylene terephthalamide) (Kevlar) and poly(p-benzamide), by DuPont de Nemours Co. in the 1970s. These aromatic polyamides form LC states when dissolved in a solvent (lyotropic), such as sulfuric acid. In addition, the commercialization of aromatic polyesters (e.g., Xydar® and Vectra®) that form LC states in melts (thermotropic) in the 1980s sparked the continued and unabated growth of the field of LC polymers (LCPs). Wholly aromatic LCPs are highly crystalline, insoluble, and very often interactive materials. These polymers have a very high melting temperature, and, thus, they cannot be readily processed by spinning or molding. However, LCPs should be structurally modified to overcome these processing issues and prevent their thermal degradation before melting. The most common method for structural modification is to combine different mesogenic monomers, such as bulky side substituents, flexible alkyl side groups, or kink (nonlinear)-structured monomers.

Nanocomposites are one of the most important classes of synthetic engineering materials. The incorporation of organic/inorganic hybrids can yield materials that possess excellent stiffness, strength, and gas barrier properties with far less inorganic content than is used in conventionally filled polymer composites: the higher the degree of delamination in polymer/nanofiller composites, the greater the enhancement of these properties. Nanofillers can be categorized on the basis of their dimensions, such as one-dimensional fillers (nanotubes and nanowires), two-dimensional fillers (clays and graphene), and three-dimensional fillers (spherical and cubic nanoparticles).

This Special Issue, entitled “Liquid Crystalline Polymers and Their Nanocomposites”, will consider a broad range of LCPs, such as engineering materials for high-performance LCPs, high-temperature LCPs, and new synthetic LCPs. This Special Issue will also consider LCP blends with engineering polymers and organic–inorganic LCP nanocomposites.

Prof. Dr. Jin-Hae Chang
Guest Editor