Self-assembly and entropic effects in pear-shaped colloid systems. I. Shape sensitivity of bilayer phases in colloidal pear-shaped particle systems

Abstract

Self-assembly and entropic effects in pearshaped colloid systems. I. Shape sensitivity of bilayer phases in colloidal pearshaped particle systems. The Journal of Chemical Physics, 153 (3), 034903-034903.

Self-assembly and entropic effects in pear-shaped colloid systems: II. Depletion attraction of pear-shaped particles in a hard sphere solvent

“…Here, the contact coincides with the Bézier description to much higher accuracy (essentially only limited by the discretisation used for the mesh). Even though the difference between the PHGO and the HPR model is small (see in-depth discussion about the differences in the contact function in part 1), the first part of this study shows that the gyroid phase is not formed by HPR particle [13].…”

“…that during the rearrangement of inversion asymmetric particles from a configuration where the colloids are separated to one where they are in contact due to depletion interactions, the colloids are likely to first approach each other with their bigger ends before eventually equilibrating into the most compact formation. Note that an indication of this blunt-endattraction can be seen in the gyroid-phase self-assembly [13] where the blunt ends form the network-like domains of the bicontinuous cubic phase [15][16][17]. This indicates that also the hard HPR pears has a tendency to cluster with their blunt ends.…”

“…This is manifested in the contact distance of roughly perpendicular arrangements (see Fig. 1 of part 1 [13]). Here, the pear size is overestimated, and a particle pair is accounted as overlapping even though they are not in contact according to the Bézier-curve depiction.…”

“…We show that also the excluded volume interactions of pears in a solvent of hard spheres are impacted by these distinctions. This depletion behaviour enables us to explain some of the differences between the PHGO and HPR selfassembly behaviour of the pure systems, without solvent which were discussed in part 1 of this series [13].…”

“…Pear-shaped colloids, or rather their contact function, have been modelled using the self-non-addivitive pear hard Gaussian overlap (PHGO) model which is a computationally much faster approximation than the proper hard pears of revolution (HPR) model. We showed in part 1 [13] and other earlier studies that pear-shaped particles, which contact is approximated by the PHGO potential [14], spontaneously form cubic, bicontinuous phases, like the double gyroid [15,16] or, when diluted with a small amount of hard-sphere solvent, the double diamond [17]. We define pear-shaped particles by the Bézier-curve which, when extended to a solid of revolution, yields the pear-shaped particle shape with a smooth bounding surface [14] (see also FIG.…”