David W. Allender

Past Physics Chair (1995-2001)

Working in close co-operation with experimentalists in the Physics Department and Liquid Crystal Institute, Professor Allender and his students apply various techniques of theoretical condensed matter physics to the description of liquid crystal materials and the wide variety of phase transitions they undergo. These transitions can be induced by varying temperature, the nature of the surfaces confining the liquid crystal sample, and the direction and strength of electric, magnetic and optical fields.

As an example, Allender's group has used Landau's concepts of phase transitions and ordering to study liquid crystalline material confined to sub-micron cavities where the effects of the surface can produce behavior quite different from bulk systems. Novel elastic properties were predicted and subsequently verified experimentally. Other topics of recent interest include biaxiality at the surface and in the bulk, field effects in chiral phases, and periodic structure formation. The ideas developed here are useful in other areas of condensed matter physics such as melting, the spontaneous growth of spatially periodic structures, and optics.

Allender maintains active collaborations with numerous groups including colleagues at the Weizmann Institute of Science in Israel and the University of Ljubljana in Slovenia. Continuity with forefront research is facilitated by involvement with both national and international conferences. 

Scholarly, Creative & Professional Activities

• Phase Separation in Bilayer Lipid Membranes: Effects on the Inner Leaf due to Coupling to the Outer Leaf (Submitted to Biophysical J) (PDF)
• Approximate description of the two-dimensional director field in a liquid crystal display (PDF)
• Model for the director and electric field in liquid crystal cells having twist walls or disclination lines (PDF)
• Pseudo-Casmir effect in twisted chiral nematic liquid crystals (PDF)
• Geometrical optics approach in liquid crystal films with three dimensional director variations (PDF)
• Calorimetric study of nematic prewetting (PDF)
• Surface states in nearly modulated systems (PDF)