Significance Assembling optical metamaterials from DNA-coated colloids has been a central goal of programmable self-assembly for decades. Despite significant advances in expanding the structural diversity of colloidal crystals, a lack… Click to show full abstract
Significance Assembling optical metamaterials from DNA-coated colloids has been a central goal of programmable self-assembly for decades. Despite significant advances in expanding the structural diversity of colloidal crystals, a lack of understanding of the crystallization pathways has hindered the realization of programmable metamaterials. In this paper, we combine experiments and theory to develop a complete understanding of the crystallization dynamics. We show that the nucleation and growth kinetics of DNA-coated colloids are fundamentally different from those of atoms or small molecules, owing to an effective friction that arises from transient DNA hybridization. By incorporating this effective friction into classical theories, we predict the absolute rates of nucleation and growth with quantitative accuracy, enabling the design of protocols for making photonic crystals. DNA-coated colloids can self-assemble into an incredible diversity of crystal structures, but their applications have been limited by poor understanding and control over the crystallization dynamics. To address this challenge, we use microfluidics to quantify the kinetics of DNA-programmed self-assembly along the entire crystallization pathway, from thermally activated nucleation through reaction-limited and diffusion-limited phases of crystal growth. Our detailed measurements of the temperature and concentration dependence of the kinetics at all stages of crystallization provide a stringent test of classical theories of nucleation and growth. After accounting for the finite rolling and sliding rates of micrometer-sized DNA-coated colloids, we show that modified versions of these classical theories predict the absolute nucleation and growth rates with quantitative accuracy. We conclude by applying our model to design and demonstrate protocols for assembling large single crystals with pronounced structural coloration, an essential step in creating next-generation optical metamaterials from colloids.
               
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