Regioregular poly(3-hexylthiophene) (rr-P3HT) nanofibers offer a combination of simple, low-cost fabrication and inherently high crystallinity, making them promising materials for use as conductive polymer semiconductors in organic electronics. This study clarified how solvent vapor annealing (SVA) using chloroform as the solvent improves the internal structure of poly(3-hexylthiophene) (P3HT) nanofibers and consequently enhances their electrical performance. Nanofibers were fabricated from an anisole/chloroform mixture (3:7 v/v) and subsequently exposed to chloroform vapor for 6–12 h (powder samples) or 15–60 min (thin film mats). X-ray diffraction (XRD) analysis retained the native (100) and (020) reflections while also revealing higher-order (200), (300), and (400) peaks, along with a new (020)* peak associated with an enhanced crystallographic packing density along the π–π stacking direction as a result of the SVA treatment. The crystalline coherence length along the π–π stacking direction increased substantially from 32 Å in the pristine state to 82 Å after 12 h of SVA treatment. Simultaneously, the broad amorphous peak between 15° and 28° decreased, indicating the partial conversion of disordered regions into well-ordered crystalline domains. Scanning electron microscopy and atomic force microscopy analyses confirmed that the nanofiber morphology remained intact under the optimized SVA conditions. A bottom-gate field-effect transistor fabricated from rr-P3HT nanofiber mats exhibited p-type charge transport characteristics. After 60 min of SVA, the linear-regime mobility had increased by a factor of 1.3, from 5.27 × 10^-3 to 6.86 × 10^-3 cm² V^-1 s^-1, which was accompanied by a reduced threshold voltage. The carrier mobility enhancement scaled positively with the SVA duration and showed a strong correlation with the increase in the crystalline coherence length. These findings collectively demonstrate that optimized chloroform SVA is a highly effective post-treatment strategy for densifying π–π stacking and improvin g charge transport without compromising the nanofiber morphology.

Regenerated silk fibroin (SF) nanofibers are known for their brittleness, which poses challenges for practical applications. Moreover, the complete removal of sericin (SS) adversely affects the mechanical properties of SF. This study presents an innovative, green, one-step method for extracting nano-fibrillated SF using only water, through a combination of autoclaving and grinding treatments. Silk fibers (SF/SS) were autoclaved for varying durations to retain different amounts of SS and enhance mechanical performance. A series of SF/SS samples with different degumming times was prepared to assess the influence of SS content before and after film formation. A set of fibroin–sericin-based nano-fibrillated (FNF/SS) composite films with improved mechanical properties was developed. Controlled SS content significantly enhanced the mechanical performance of SF.

In this study, we focused on the formation of metal complexes with dyes and investigated the relationship between dyeing procedures and lightfastness. We investigated the lightfastness of dyed materials containing alizarin and purpurin―key dye components of madder―under different mordant and dyeing conditions. The stability of the examined dyes under light exposure depended strongly on the type of metal mordant used and the pH of the dyeing environment. These results indicate that dye–metal complex formation depends strongly on the dyeing conditions, and in turn, affects the lightfastness of the dyed materials. Variations in complex formation behaviors were reflected in the fluorescence emission spectra of the examined dyes. Although natural dyes are generally considered to have poor lightfastness, our results demonstrated that the formation of dye–metal complexes can substantially enhance their photostability. Therefore, careful selection and optimization of the dyeing method and conditions could help design a suitable strategy for improving the lightfastness of natural dyes.