Cellulose-based liquid crystalline photoresponsive films with tunable surface wettability

A self-cleaning and photocatalytic cellulose-fiber- supported "Ag@AgCl@MOF- cloth'' membrane for complex wastewater remediation

Membrane technology is one of the most promising technologies for wastewater remedy. However, it remains challenging to prepare high-performance membrane matrix for complex pollutants, e.g. containing both oil and organic dye. In this work, we facilely fabricate a cellulose-fiber-supported MOF photocatalytic membrane, namely Ag@AgCl@MIL-100(Fe)/CCF, which was prepared via carboxymethylation of cotton fabric (CCF) as scaffold and in-situ synthesis of MOF derivative as photocatalyst. The carboxymethylation significantly improves the hydrophilicity of cotton fabric and the deposition amount of MIL-100(Fe). The high hydrophilicity of modified CCF and porous MIL-100(Fe) further enable the membrane with an efficient adsorption capacity of dyes and underwater oleophobicity against oils. The photocatalysts Ag@AgCl nanoparticles anchored onto MIL-100(Fe) promote the photocatalytic activity. As a result, the membrane shows simultaneous high removal efficiency towards dyes (97.3 %) and oils (99.64 %). Additionally, thanks to the good photocatalytic activity against organic pollutants, the membrane exhibits excellent self-cleaning and a long-term reuse capacity.

Combined Chemical Groups and Topographical Nanopattern on the Poly(ε-Caprolactone) Surface for Regulating Human Foreskin Fibroblasts Behavior

Surface chemistry and substrate topography could contribute significantly to providing a biochemical and topographical cues for governing the fate of cells on the cell-material interface. However, the synergies between these two properties have not been exploited extensively for biomaterial design. Herein, we achieved spatial-controlled patterning of chemical groups on the poly(ε-caprolactone) (PCL) surface by elegant UV-nanoimprint lithography (UN-NIL). The introduction of chemical groups on the PCL surface was developed by our newly 6-benzyloxycarbonylmethyl-ε-caprolactone (BCL) monomer, which not only solved the lack of functional groups along the PCL chain but also retained the original favorable properties of PCL materials. The synergetic effect of the chemical groups and nanopatterns on the human foreskin fibroblasts (HFFs) behaviors was evaluated in detail. The results revealed that the patterned functional PCL surfaces could induce enhanced cell adhesion and proliferation, further trigger changes in HFFs morphology, orientation and collagen secretion. Taken together, this study provided a method for straightforward fabrication of reactive PCL surfaces with topographic patterns by one-step process, and they would facilitate PCL as potential candidate for cell cultivation and tissue engineering.

How thermal curing of an organic paper coating changes topography, chemistry, and wettability

Celluloses are preferred renewable substrates, but hydrophilicity and porosity disfavor their water resistance. We present here an ecofriendly application of imidized nanoparticles and a method to flexibly tune the surface wettability of papers. The soft nanostructured coating is sensitive to thermal curing, which affects both the surface chemistry and morphology. The thermal stability of the coating is first investigated with conventional and modulated differential scanning calorimetry, revealing influences of the imide content and an endotherm reaction below the glass transition temperature at 120-150 °C. The latter is studied in detail for an appropriate selection of the copolymer precursors. According to diffuse reflection infrared spectroscopy, Raman spectroscopy, and UV/vis spectroscopy, the endotherm corresponds to an imidization reaction. The morphology of the coatings is followed at various scale levels by contactless roughness measurements and atomic force microscopy. Finally, the experimental values are fitted to the parameters of the Wenzel wetting model, and so-called calibration curves for the relation between contact angles, surface roughness, and surface chemistry are presented. They allow the prediction of the water contact angle of coated papers from the hydrophilic to the hydrophobic range, with a maximum in hydrophobicity after increasing the imide content at 120-150 °C curing.