Multistep kinetic self-assembly of DNA-coated colloids

Abstract

Equilibrium self-assembly relies on the relaxation of disordered mixtures of building blocks towards an ordered ground state. The main drawback of this traditional approach lies in the kinetic traps that often interrupt the progression of the system towards equilibrium and lead to the formation of arrested phases. The latest techniques to control colloidal interactions open up the possibility of exploiting the tendency to dynamically arrest in order to construct amorphous materials with a specific morphology and local separation between multiple components. Here we propose strategies to direct the gelation of two-component colloidal mixtures by sequentially activating selective interactions. We investigate morphological changes in the structure of the arrested phases both by means of molecular dynamics simulations and experimentally by using DNA-coated colloids. Our approach can be exploited to assemble multicomponent mesoporous materials with possible applications in hybrid photovoltaics, photonics and drug delivery.

Temperature (de)activated patchy colloidal particles

“…Therefore, by using patches coated with distinct DNA sequences one might fabricate complex patchy colloids with distinct activation temperatures. This method has been used in [12] to design a multistep self-assembly in isotropically DNA-coated colloids. Also, in [13] a binary system of DNA-coated colloids was investigated using Monte Carlo simulation.…”

Measuring local volume fraction, long-wavelength correlations, and fractionation in a phase-separating polydisperse fluid

“…The results show emphatically that complex fractionation is involved right from the beginning of polydisperse phase separation, local composition relaxing alongside local density rather than long after it. It can therefore play a role in the formation of nonequilibrium structures which arrest before coming to equilibrium 27,28 , such as when gels form from a polydisperse colloid 2 . As well as fractionation, the correlation functions introduced could be of general use in characterising structural effects of polydispersity.…”

“…There is scant data on how these systems behave whilst evolving towards their fractionated equilibria [24][25][26] . This may be especially important where phase separation serves as a route to some nonequilibrium arrested state 27,28 -in such cases, the true compositional equilibrium (in terms of fractionation) may never be reached. In other cases, fractionation is required in order to even access the equilibrium phase 11 , so that the dynamics of fractionation directly influences whether the system can equilibrate in any meaningful sense 2 .…”

Colloquium : Toward living matter with colloidal particles

“…The interactions between different colors can be made orthogonal to one another by judicious choices of the sequences. Such schemes have been used to assemble colloidal crystals (Auyeung et al, 2014;Kim et al, 2006;Macfarlane et al, 2011;Martinez-Veracoechea et al, 2011;Nykypanchuk et al, 2008;Park et al, 2008), gels (Di Michele et al, 2013), and clusters (McGinley et al, 2013;Schade et al, 2013).…”