Polymeric crystallization under nanoscale 2D spatial confinement

A study was conducted to investigate the way crystal nucleation and growth were related to the effects of altered size of cylindrical spatial confinement. It was demonstrated that reducing confinement space to an effective size made it possible to nucleate homogeneously as governing an overall crystallization process, while reducing confinement space caused the crystal growth of PCL blocks changing from preferred crystalline orientation to random orientation. Semicrystalline P4VP-PCL block copolymers (BCPs) were synthesized through living ring-opening polymerization (ROP) and atom-transfer radical polymerization (ATRP) in sequence. Bulk sample of BCPs were prepared by solution casting from dichloromethane (CH₂Cl₂) solution at room temperature. The cylinder-forming samples were also subjected to a large-amplitude oscillating shear at 190 °C to examine the grown crystal orientation under confinement and achieve a uniform, parallel alignment of the cylindrical microdomains.