ABSTRACT
In this work, a functionalized polycaprolactone (PCL) composite fiber combining calf-type I collagen (CO) and natural drug usnic acid (UA) was prepared, in which UA was used as an antibacterial agent. Through 3D near-field electrospinning, the mixed solution was prepared into PCL/CO/UA composite fibers (PCUCF), which has a well-defined perfect arrangement structure. The influence of electrospinning process parameters on fiber diameter was investigated, the optimal electrospinning parameters were determined, and the electric field simulation was conducted to verify the optimal parameters. The addition of 20% collagen made the composite fiber have good hydrophilicity and water absorption property. In the presence of PCUCF, 1% UA content significantly inhibited the growth rate of Gram-positive and negative bacteria in the plate culture. The AC-PCUCF (after crosslinking PCUCF) prepared by crosslinking collagen with genipin showed stronger mechanical properties, water absorption property, thermal stability, and drug release performance. Cell proliferation experiments showed that PCUCF and AC-PCUCF had no cytotoxicity and could promote cell proliferation and adhesion. The results show that PCL/CO/UA composite fiber has potential application prospects in biomedical dressing.
ABSTRACT
Currently, the degradation of organic pollutants in wastewater by photocatalytic technology has attracted great attention. In this study, a new type of 3D printing material with photocatalytic activity was first prepared to print a water treatment equipment, and then a layer of silver-loaded TiO2 was coated on the equipment to further improve the catalytic degradation performance. The composite filaments with a diameter of 1.75 ± 0.05 mm were prepared by a melt blending method, which contained 10 wt% of modified TiO2 and 90 wt% of PLA. The silver-loaded TiO2 was uniformly coated on the equipment through a UV-curing method. The final results showed that those modified particles were uniformly dispersed in the PLA matrix. The stable printing composite filaments could be produced when 10 wt% TiO2 was added to the PLA matrix. Moreover, the photocatalytic degradation performance could be effectively improved after 5 wt% of silver loading was added. This novel facility showed good degradability of organic compounds in wastewater and bactericidal effect, which had potential applications for the drinking water treatment in the future.
ABSTRACT
A series of nonplanar tri-s-triazine-based molecules were designed, and their optical, electronic, and charge transport properties as ambipolar host materials for blue electrophosphorescence emitters were explored by density functional theory. The influence of the linkage between tri-s-triazine and carbazole, diphenylamine and triphenylamine, as well as the influence of a series of electron-donating and electron-withdrawing substituents on triplet energy, energy level matching and charge transport of the designed molecules was discussed in detail. Our results reveal that the molecules under investigation can serve as host materials for blue electrophosphorescence emitters. We also predicted the mobility of designed molecules with better performance in the P1[combining macron] space group. Based on the investigated results, we proposed a rational way for the design of host materials for OLEDs, and also expanded the application field of tri-s-triazine.
