Axially oriented guest induced crystallization in syndiotactic polystyrene unstretched fibers

Thymol and Carvacrol: Phenolic Monoterpenes Extracted from the Essential Oil of Thymus vulgaris as Natural Antimicrobial Guests of Nanoporous Crystalline Syndiotactic Polystyrene Fibers

“…2D-patterns in Figure 2b',c' exhibit one single equatorial peak located at 2𝜃 value of ≈9.8°, due to the presence of the crystalline disordered phase which is a modification formed of small bundles of s(2/1)2 helical chain with typical periodicity of 0.78 nm. [41,50] s-PS fibers after treatments by pure carvacrol or thymol/methyl acetate solution have also been characterized by FTIR analysis (Figure 3). Particularly informative is the spectral region 3150-3750 cm -1 showing a broad band centered at ≈3400 cm -1 present in pure carvacrol and thymol and a new sharp band located at 3540 cm −1 for thymol co-crystalline sample (curve b) and 3552 cm -1 for carvacrol co-crystalline sample (curve c).…”

“…[23][24][25][26][27] To combat the burst release, a multilayer system with a secondary matrix can be also used, this new system would act as a double barrier inhibiting the leakage of Eos. [28] Interesting can be the capability of commercial polymers like syndiotactic polystyrene (s-PS) [29][30][31][32][33][34][35][36][37][38][39][40][41] and poly(2,6-dimethyl-1,4phenylene)oxide (PPO) [42][43][44][45][46] to crystallize with suitable guest molecules leading to co-crystalline (CC) phases in which the guest molecules are included inside the crystalline lattice. In particular, guest molecules involved in the formation of CC phases can be, for instance, fluorescent, [33,34] photoreactive, [35,36,46] chiral, [37,38] and antimicrobial [39][40][41] molecules leading to materials with specific characteristics.…”

“…[28] Interesting can be the capability of commercial polymers like syndiotactic polystyrene (s-PS) [29][30][31][32][33][34][35][36][37][38][39][40][41] and poly(2,6-dimethyl-1,4phenylene)oxide (PPO) [42][43][44][45][46] to crystallize with suitable guest molecules leading to co-crystalline (CC) phases in which the guest molecules are included inside the crystalline lattice. In particular, guest molecules involved in the formation of CC phases can be, for instance, fluorescent, [33,34] photoreactive, [35,36,46] chiral, [37,38] and antimicrobial [39][40][41] molecules leading to materials with specific characteristics. Moreover, by removing guest molecules from CC phase, nanoporous crystalline (NC) phases, presenting a density lower than the corresponding amorphous phases, can be easily obtained for s-PS [47][48][49][50] as well as for PPO.…”

“…Interesting can be the capability of commercial polymers like syndiotactic polystyrene (s‐PS) [ 29–41 ] and poly(2,6‐dimethyl‐1,4‐phenylene)oxide (PPO) [ 42–46 ] to crystallize with suitable guest molecules leading to co‐crystalline (CC) phases in which the guest molecules are included inside the crystalline lattice. In particular, guest molecules involved in the formation of CC phases can be, for instance, fluorescent, [ 33,34 ] photoreactive, [ 35,36,46 ] chiral, [ 37,38 ] and antimicrobial [ 39–41 ] molecules leading to materials with specific characteristics.…”

Monomeric and Dimeric Carboxylic Acid in Crystalline Cavities and Channels of Delta and Epsilon Forms of Syndiotactic Polystyrene

“…In particular, for the δ form film, the equatorial peak at 2θ = 8.7 • and the shoulder at 2θ ≈ 10 • of the triclinic NC δ phase are replaced by a single diffraction peak at 2θ = 9.8 • , typical of the disordered CC form [51]. Analogously, for the ε form film, the intensity of the equatorial (110) and (020) peaks at 2θ = 6.9 • and 8.2 • , respectively, is markedly decreased with respect to the intensity of the first-layer line reflections (mainly that one at 2θ ≈ 20.2 • ), as is typical of CC ε form films [19,23].…”