Homogeneous Crystal Nucleation Triggered by Spinodal Decomposition in Polymer Solutions

Abstract

We report dynamic Monte Carlo simulations of polymer crystal nucleation initiated by prior spinodal decomposition in polymer solutions. We observed that the kinetic phase diagrams of homogeneous crystal nucleation appear horizontal in the concentration region below their crossovers with the theoretical liquid-liquid spinodal. When the solution was quenched into the temperature beneath this horizontal boundary, the time evolution of structure factors demonstrated the spinodal decomposition at the early stage of crystal nucleation. In comparison with the case without a prior liquid-liquid demixing, we found that the prior spinodal decomposition can regulate the nanoscale small polymer crystallites toward a larger population, more uniform sizes, and a better spatial homogeneity, whereas chain folding in the crystallites seems little affected.

Synthesis of semicrystalline nanocapsular structures obtained by Thermally Induced Phase Separation in nanoconfinement

“…2c ), presuming the coexistence of curved crystals within the shell. In this case, explanations of crystallization behavior belonging to the produced nanocapsules can be again associated with the crystal growth in the confined and curved volume of a droplet, where a TIPS process, occurring at curved liquid/liquid-droplet interface, can bring to unusual polymer solution crystallization 50 51 52 . This peculiar thermal behavior can indicate, therefore, that the crystallization path is confinement dependent.…”

“…Subsequently, some folded chains immediately aggregate, leading to the formation of crystal nuclei within the droplet. However, at this point, further aggregation phenomena are prevented by a large energy barrier due to intersegment attractive and repulsive interactions, volume effects and presence of antisolvent: only the development of interconnected domains characteristic of spinodal decomposition can proceed 50 51 61 .…”

Role of Block Junctions in the Interplay of Phase Transitions of Two-Component Polymeric Systems

“…In addition, for such blends near the melting points, thermal fluctuations toward crystalline order will significantly enhance liquid–liquid demixing . On the other hand, polymer crystal nucleation could be triggered by the prior liquid–liquid demixing in polymer solutions . In addition, the interfaces between two incompatible components in polymer blends will enhance crystal nucleation, while such an effect occurs only with poor enough solvent in polymer solutions …”

Membrane formation of poly(vinylidene fluoride)/poly(methyl methacrylate)/diluents via thermally induced phase separation

“…In the TIPS process, the thermodynamics of polymer/diluent system, especially for the thermodynamic interaction between polymer and diluent in their mixture during the phase separation process, has been studied systematically 11–13. The phase separation dominating solid‐liquid (S‐L) or liquid‐liquid (L‐L) phase separation with subsequent polymer crystallization can be controlled through the appropriate choice of diluent,1, 2, 14 and significantly influence the crystallization morphologies of polymer (crystalline or semicrystalline) 3, 15…”