The Single-Polymer Micelle

People

• Brian Moths

  PhD 2018

• Tom Witten

Funding

Partial: UCHICAGO MRSEC, National Science Foundation, award number 1420709

Talks

Our Papers

Engineering single-polymer micelle shape using non-uniform spontaneous surface curvature Authors: Brian Moths, Thomas A. Witten Physical Review E. 97 032505 (2018) Conventional micelles, composed of simple amphiphiles, exhibit only a few standard morphologies, each characterized by its mean surface curvature set by the amphiphiles. Here we demonstrate a rational design scheme to construct micelles of more general shape from polymeric amphiphiles. We replace the many amphiphiles of a conventional micelle by a single flexible, linear, block copolymer chain containing two incompatible species arranged in multiple alternating segments. With suitable segment lengths, the chain exhibits a condensed spherical configuration in solution, similar to conventional micelles. Our design scheme posits that further shapes are attained by altering the segment lengths. To assess the power of this scheme, we exhibit stable micelles of horseshoe form using conventional bead-spring simulations in two dimensions. Modest changes in the segment lengths produce smooth changes in the micelle's shape and stability.

Feasibility of rational shape design of single-polymer micelle using spontaneous surface curvature, Authors: Brian Moths Physical Review E submitted March 2018 , Abstract:Polymeric micelles are used in a variety of applications, with the micelle's shape often playing an important role. Consequently, a scheme to design micelles of arbitrary shape is desirable. In this paper, we consider micelles formed from a single, linear, multiblock copolymer, and we study how easily the micelle's shape can be controlled by altering the copolymer block lengths. Using a rational design scheme, we identify a few aspects of the multiblock composition that are expected to have a well-behaved, predictable effect on micelle shape. Starting from a reference micelle composition, itself already exhibiting a nonstandard shape having a moderately sized dimple, we alter these aspects of the multiblock composition and observe the regularity of the micelle shape response. The response of the shape is found to be somewhat smooth, but significantly nonlinear and sometimes nonmonotonic, suggesting that sophisticated techniques may be required to aid in micelle design.