AUTHOR=Wang Hai , Men Yongfeng , Tashiro Kohji 

TITLE=Solvent-induced crystallization and phase-transition phenomena in syndiotactic polystyrene and its relatives

JOURNAL=Frontiers in Soft Matter

VOLUME=2

YEAR=2022

URL=https://www.frontiersin.org/journals/soft-matter/articles/10.3389/frsfm.2022.1041872

DOI=10.3389/frsfm.2022.1041872

ISSN=2813-0499

ABSTRACT=<p>The studies of time-dependent structural changes in the solvent-induced crystallization and phase transition phenomena have been reviewed by focusing mainly on syndiotactic polystyrene (SPS) and its relatives having the functional groups on the phenyl rings. The time-resolved measurement of X-ray diffraction and vibrational spectra has revealed the structural evolution process in the solvent-induced crystallization of SPS, which depends on the type (polarity, bulkiness, etc.) of the solvent molecules. The heating of the SPS-solvent complexes causes the complicated phase transitions from the <italic>δ</italic> form (complex) to the <italic>γ</italic> form and to the <italic>α</italic> (or <italic>β</italic>) form. The introduction of such a polar functional group as OCH<sub>3</sub> or halogen units on the phenyl rings enhances the interactions between the SPS and the solvent, the strength of which depends on the substitution position of the OCH<sub>3</sub> units on the phenyl ring. For example, the ortho- or para-substitution dissolves the sample quite easily at room temperature, while the meta-substitution makes it possible to create the solvent complexes. The discussion has been made for the structural relation before and after the formation of the solvent-complexes.</p>