Using the conformational entropy of polymer chains for directed self-assembly of colloids.

Directed self-assembly of colloids is generally practiced through engineering particle interactions or the energy related to the particle domains, such as surface energy density. In this talk, a new strategy for directed self-assembly of colloids employing the entropy of polymer chain conformations is discussed. By locating long polymer chains in the interstitial space of colloidal crystals and letting the chains configure the interstitial space to maximize the chain conformation entropy, directed self-assembly of colloids coupled with the interstitial space configuration selected by the chains is achieved. Using model spherical block copolymer colloids, the chain conformational entropy to control the polytypic states of close-packed structures is documented, and the quantitative relationships between the chain conformational entropy and the lattice entropy are examined. This work demonstrates that polymer chains can serve as a new director for the self-assembly of colloids, in particular, to control polymorphism.