Polymeric Films with Three Different Uniplanar Crystalline Phase Orientations

Abstract

Semicrystalline syndiotactic polystyrene (s-PS) films, for all crystalline phases based on helical chains (δ, γ and clathrates), have been prepared with high degrees of three different kinds of uniplanar orientation. In particular, by suitable solution- or solvent-induced crystallizations, (010), (002), or (2̄10) crystalline planes of the nanoporous δ and clathrate phases can be oriented preferentially parallel to the film plane. To our knowledge, the achievement for a given polymeric crystalline phase of high degrees of three different uniplanar orientations is unprecedented. This is particularly relevant for s-PS due to the functional properties of its nanoporous crystalline δ phase as well as of its clathrate phases. As for the clathrate phases, it is also worth noting that, since each cavity of the clathrate phase generally includes one isolated guest molecule whose mobility is generally low, the control of the orientation of the host crystalline phase also allows the control of the orientation of the guest molecules.

Polymorphism of syndiotactic polystyrene: γ phase crystallization induced by bulky non-guest solvents

“…The degree of uniplanar orientation of the crystallites with respect to the film plane has been formalized on a quantitative numerical basis using Hermans' orientation functions [32,[44][45][46][47], in analogy to that one defined for the axial orientation in Ref.…”

“…A (200) uniplanar orientation of the g-phase was already obtained by annealing of d-phase films presenting a ð 210Þ crystalline phase orientation [47].…”

Crystalline Complex of Syndiotactic Polystyrene with Poly(ethylene Glycol) Dimethyl Ethers

“…sPS can form co-crystal structures of high crystallinity with a variety of low mass molecules and the degree of orientation and the direction of the crystal axes are adjustable. [37,38,16] It seems that the approach we have applied in this study is a promising method to build interpolymer crystalline complexes whose frame work is composed of the (T 2 G 2 ) 2 helices of sPS. Further studies are ongoing, evaluating the possibility of the complexation of higher molecular weight poly(ethylene glycol) and other polymeric materials and also investigating more detailed structural information.…”

Understanding at molecular level of nanoporous and co-crystalline materials based on syndiotactic polystyrene

“…Although, as usual, hopping events are facilitated by transient channels of free volume between existing cavities and the channels are formed by thermal motions of the host polymer atoms [83][84][85][86], for a nanoporous crystal phase average sizes and locations of the cavities, as well as crystallographic directions of the channels, are all identical. Several recent experimental studies have shown the additional ability of s-PS, possibly unique for polymer films, to be formed with three different kinds of orientation of the helical crystalline phase [13,[87][88][89][90]. In particular, films exhibiting three different orientations of the ac layers of close-packed alternated enantiomorphous polymer helices (Fig.…”