Influence of Tie and Loop Molecules on the Mechanical Properties of Lamellar Block Copolymers

Abstract

We use coarse-grained molecular dynamics simulation to study the influence of molecular architecture and conformations on the mechanical response of lamellar nanostructured polymers. For this purpose, a recently developed generation method (radical like polymerization method) has been optimized to generate lamellar triblock copolymer samples with alternate glassy and rubbery stacks. Several systems, with various rate of loop (both ends of the chain are in the same glassy block), cilia (cut triblock, effectively a diblock chain) and tie molecules (TMs) (chain that bridges two subsequent glassy blocks through the intermediate rubbery block) were generated. Uniaxial tensile tests were performed, the tensile strain being applied in the normal direction of the lamellae. This situation can be understood as a simple way of mimicking the deformation of the equatorial stack in semicrystalline polymers, with the “hard” phase being the glassy (rather than crystalline) one. The resulting constitutive laws reveal the ...