Entropic patchiness: Effects of colloid shape and depletion

• Published in: Current opinion in colloid & interface science 2017-07, Vol.30, p.54-61
• Main Authors: Petukhov, Andrei V., Tuinier, Remco, Vroege, Gert Jan
• Format: Article
• Language: English
• ISSN: 1359-0294; 1879-0399
• DOI: 10.1016/j.cocis.2017.05.008

This paper reviews ‘entropic patchiness’ of colloidal particles. On the one hand this may be due to their intrinsic tendency to form certain shape-dependent configurations in crowded suspensions, on the other hand this can be strongly enhanced by using depletion interactions that are also of purely entropic origin. A brief account of the Onsager theory and its consequences for the formation of colloidal liquid crystals of highly anisometric particles is presented. It is further supplemented by a recap of the description of depletion attraction between colloids and the effects of their shape. A number of recent examples exploiting entropic patchiness are discussed. [Display omitted] •Non-spherical hard colloidal particles can exhibit directionality purely based on entropic interactions.•Interplay between orientational and excluded volume entropy enables to induce multiple liquid-crystalline phases.•Depletion interactions can strongly enhance entropic patchiness of hard colloids.•Variation of particle shape, strength and range of depletion attraction yields a wide variety of self-assembled structures.