The separation of different molecular forces at the beginning of the droplet formation. Similar forces tend to stay together: pi-stacking and salt bridging are the two dominant forces in the liquid crystal droplet phase, while hydrogen bonding governs in the continuous polymer phase. 2. As the droplet size increases, the molecular interactions at the interface of the droplet phase and the continuous phase become stronger through multivalent interactions. The strengthening of interfacial molecular interactions in w/w emulsions results in the formation of a layer of polymer that coats the surface of the droplet which consequently prevents droplets from clumping together. 3. In addition, it is also proposed that when two liquid crystal droplets merge (coalescence), the orientation of the liquid crystal molecules in the two merging droplets must change to “adapt” to each other, and thus incur an energy penalty which prevent the occurrence of coalescence. This w/w emulsion also represents a new class of polymer dispersed liquid crystals(PDLC). Traditionally known PDLC consists of oil-in-water emulsion where the oily droplet is a thermotropic liquid crystal such as 4-pentyl-4'-cyanobiphenyl (5CB), and the water phase contains certain polymers. In comparison, this water-in-water emulsion consists of Polymer-Dispersed Lyotropic Liquid Crystals, where the lyotropic liquid crystal is DSCG molecules solvated in water. Traditional PDLCs have found application, from switchable windows to projection displays. The water-in-water emulsion of polymer-dispersed lyotropic liquid crystals has the potential for building highly bio-functional materials because of its compatibility with protein structure. Other known types of water-in-water emulsions involve the separation of different biopolymers in aqueous solution. References 4. (a) Terentjev, E. M. Europhys. Lett. 1995, 32, 607–612. (b) Poulin,P.; Stark, H.; Lubensky, T. C.; Weitz, D. A. Science 1997, 275, 1770–1773. 5. Scholten, E.; Sagis, L. M. C.; Van der Linden, E., Effect of Bending Rigidity and Interfacial Permeability on the Dynamical Behavior of Water-in-Water Emulsions. Journal of Physical Chemistry B 2006, 110, (7), 3250–3256. External links 1. Salt bridging and example of salt bridges http://www.cryst.bbk.ac.uk/PPS2/projects/day/TDayDiss/SaltBridges.html 2. Tutorial on liquid crystals http://outreach.lci.kent.edu/ 3. Introduction to polymer dispersed liquid crystals (PDLC) http://plc.cwru.edu/tutorial/enhanced/files/pdlc/intro/intro.htm 4. Droplet configuration of PDLC’s http://plc.cwru.edu/tutorial/enhanced/files/pdlc/droplet/droplet.htm Colloidal chemistry Soft matter Water chemistry