Multiscale
assembly of poly(3-alkylthiophene)s complexed with various
alkyl-chain surfactant architectures has been investigated in dilute
and concentrated solutions by means of ultraviolet–visible
absorption and fluorescence spectroscopy, polarized optical microscopy,
small-angle X-ray scattering, and four-point probe conductivity measurements.
Supramolecular complexation occurs via ionic interactions between
poly(3-alkylthiophene)s electrolytes and ionic surfactants. In dilute
solutions, the supramolecular complex undergoes a coil-to-rod conformational
transition as evidenced by a time-dependent chromism. Spectroscopic
studies on transition kinetics reveal an inverse first-order rate
law. While surfactant architectures significantly affect the persistence
length of the complexes, the inverse first-order rate law is maintained.
When concentrated above a critical value, the supramolecular complex
exhibits an isotropic-to-liquid crystalline transition yielding hexagonally
ordered microstructures. The liquid crystalline phase boundaries are
largely dependent on polymer and surfactant architectures. The correlations
between the intrinsic rigidity of conjugated polymers, optoelectronic
properties, and liquid crystalline formation are presented. The dried
films made from the sheared liquid crystalline solutions inherit liquid
crystalline monodomains and display four times faster charge transport
along the backbone alignment direction than the perpendicular direction.
Severinia buxifolia (Rutaceae) is often used as a traditional medical plant. The present study was carried out to estimate the effects of solvents (petroleum ether and hexane: ethyl acetate) used in liquid–liquid extraction to total terpenoid content (TTC) and in vitro anti‐inflammatory activity of the extracts obtained from S. buxifolia bark. The results showed that solvent fractionation increased the TTC compared with crude extracts. The hexane: ethyl acetate bark extract fraction (HEF) had the highest TTC (731.48 µg/ml) in comparison with the petroleum ether bark extract fraction (PEF) (564.81 µg/ml) and the crude extract (CE) (184.26 µg/ml). In addition, one of composition of terpenoid of S. buxifolia, namely ursolic acid, was determined by HPLC method from the crude CE and the fractions PEF and HEF: 2.44 μg/g DW, 3.56 μg/g DW and 5.04 μg/g DW, respectively. The samples had an in vitro anti‐inflammatory activity comparable with that of two reference standards (aspirin and indomethacin). Particularly, the HEF fraction had the highest in vitro anti‐inflammatory activity (i.e., albumin denaturation: IC50 = 147.91 μg/mL, heat‐induced hemolysis: IC50 = 159.91 μg/mL, proteinase inhibition: IC50 = 117.72 μg/mL, and lipoxygenase activity: IC50 = 90.45 μg/mL). Besides, the preliminary experiments of this study were conducted to determine the influences of maceration factors (solvent type, temperature, and time) for S. buxifolia bark extract. The TTC ranged from 453.70 to 842.59 mg linalool/g DW, and the extraction yield from 2.40% to 5.120% in all extracts. Based on TTC and EY, the hexane: acetone mixture is recommended as the optimal solvent to obtain the crude bark extract (CE) at 46°C for 24 hr of maceration. Extracts of S. buxifolia bark are a promising source for the treatment of inflammatory diseases.
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