Stretch-Induced Crystallization through Single Molecular Force Generating Mechanism

A study was conducted to demonstrate the employment of a double crystallizable symmetry diblock copolymer poly(L-lactide)-b-poly(ethylene oxide) to solve the problem of flow-induced crystallization in the condensed system. The innovative approach allowed PLLA block to stretch PEO block as they were covalently linked with each other. In situ small-angle X-ray scattering (SAXS) measurements were performed using a Bruker Nanostar SAXS instrument equipped with a two-dimensional position-sensitive detector (Bruker AXS) with 512 × 512 channels. Differential scanning calorimetry (DSC) investigations were measured on a TA Instruments 2000 DSC which was calibrated using an indium standard with a precision of ±0.2 °C. The sample was kept in a brass sample holder with Kapton windows as a sandwich structure for isothermal crystallization. The single molecular force generating method demonstrated in the study was quasi-thermodynamic process, leading to quantitatively correlating molecular strain with nucleation.