Effect of secondary structure on the self-assembly of amphiphilic molecules: A multiscale simulation study

The self-assembly of amphiphilic molecules is of interest from a fundamental and practical standpoint. There has been recent interest in a class of molecules made from beta-amino acids (which contain an additional backbone carbon atom when compared with natural amino acids). Block copolymers of beta-peptides, where one block is hydrophobic and the other is hydrophilic, self-assemble into micelles. In this work, we use computer simulations to provide insight into the effect of secondary structure on the self-assembly of these molecules. Atomistic simulations for the free energy of association of a pair of molecules show that a homochiral hydrophobic block promotes self assembly compared to a heterochiral hydrophobic block, consistent with experiment. Simulations of a coarse-grained model show that these molecules spontaneously form spherical micelles. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3689298]