Patchy colloids

Bianchi E, Blaak R, Likos CN (2011) Patchy colloids state of the art and perspectives. Phys Chem Chem Phys 13 6397-6410. doi 10.1039/C0CP02296A... 

Conical square well (CS W) association sites are commonly used as a primitive model for the association potential 0. First introduced by Bol [17] and later reintroduced by Chapman et al. [18, 19], CSWs consider association as a square well interaction which depends on the position and orientation of each molecule. Kem and Frenkel [20] later realized that this potential could describe the interaction between patchy colloids. For these CSWs the association potential is given by... 

One of the main assumptions in the development of Wertheim s first-order thermodynamic perturbation theory (TPTl) is that association sites are singly bondable. Indeed, the entire multi-density formalism of Wertheim is constructed to enforce this condition. For the case of hydrogen bonding, the assumption of singly bondable sites is justified however for patchy colloids (see Section I for a background on patchy colloids), it has been shown experimentally [42, 43] that the number of bonds per patch (association site) is dependent on the patch size. It has been 30 years since Wertheim first published his two-density cluster... 

Figure 5. Associated clusters for patchy colloids with a single double bondable patch (a) dimers, (b) chains with double bonded sites, and (c) triatomic rings of double-bonded sites. (See insert for color...

Singly bondable association sites— Assumes each association site saturates after sharing in a single association bond. This approximation is not valid for patchy colloids with large patch sizes [43]. 

The sea water in this area is enriched in some metals compared with the world average sea water. Especially, iron and man nese are present in higher quantities, the iron quantity is several times larger than the quantity of manganese. The patchy distribution of this enrichment seems to be caused by the colloidal stage of iron and manganese hydroxides ... 

Along this line of using amphiphilic features of particles to drive assembly using a hydrophobic effect, there has been a recent surge of interest in the fabrication and behavior of anisotropic patchy or Janus-type colloidal particles as a promising route to innovative nanocomposite materials [40, 41]. Whereas a thorough review lies outside our scope, we would like to highlight a few examples. Muller and coworkers prepared disc-like polymer Janus particles from assem-... 

Janus particles have equal phase-separated domains which can be located either in the core or in the corona (if present), whereas multicomparOnent particles can be generally defined as a colloidal structures which are composed of multiple phase-separated domains in the core. Particles with patches on the surface are called patchy particles and have potential applications in electronics and targeted drug delivery. Furthermore, Janus or multicompartment particles with patches on the surface can be called patchy-Janus particles or patchy-multicompartment particles, respectively. 

Throughout this chapter association has been defined as being between two molecules that must be positioned and oriented correctly for association to occur. That is, both molecules participating in the association bond have directional association sites. Another common case would be an association interaction between two molecules where one has a directional association site, while the other has a spherically symmetric association site. This type of interaction could describe ion-water solvation or mixtures [42] of patchy and spherically synunet-ric colloids. 

Bao H, Peukert W, Taylor RK One-pot colloidal synthesis ofplasmonic patchy particles, Adp Mater 23 2644-2649, 2011. 

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