A braid-reinforced hollow fiber membrane with mechanically stable coating layer was prepared by coating a blended polymer dope solution on an alkaline-treated poly(ethylene terephthalate) (PET) braid. The alkaline treatment was carried out to endow the PET braid surface with more polar groups and better hydrophilicity. The results showed that the bonding strength between the hydrophilic coating layer and modified PET braid was about two times as great as that between the coating layer and original PET braid, while the pure water permeability (PWP) of the membrane remained unchanged when the PET braid was simply treated in 3 wt % potassium hydroxide (KOH) solution at 90 8C for 1 h or 1 wt % KOH solution for 6 h. The proposed modification approach proved to be a facile, low-cost, and effective method to improve bonding strength between the coating layer and the braid, while other properties, such as PWP and morphology of the coating layer, of the braid-reinforced hollow fiber membranes were not altered, indicating promising potential in membrane engineering.
This study reports a novel carboxylated nanodiamond (CND)-enhanced self-cleaning antifouling catalytic membrane. Four poly(vinylidene fluoride) (PVDF)-based membranes (PVDF, P-CND, P-TiO 2 , and P-CND/TiO 2 ) were fabricated by non-solvent-induced phase separation. The membrane pore size, porosity, hydrophilicity, and permeability were in the same order of: PVDF < P-CND < P-TiO 2 < P-CND/TiO 2 , suggesting that CND and TiO 2 had a synergetic effect in improving these parameters. The two membranes containing CNDs (P-CND and P-CND/TiO 2 ) had the highest flux recovery ratios (∼80%) but lowest irreversible fouling ratios (∼20%), indicating that CNDs significantly enhanced the antifouling performance of the membrane. CNDs effectively improved the photodegradation performance of the TiO 2 membrane, rendering the catalytic membrane with better self-cleaning properties. This study provides an effective strategy for engineering antifouling, self-cleaning photocatalytic membranes. The engineered catalytic membrane with excellent antifouling and self-cleaning properties could be used for the degradation of various organic contaminants in wastewater treatment and reclamation.
Structural
bone allograft transplantation remains one of the common
strategies for repair and reconstruction of large bone defects. Due
to the loss of periosteum that covers the outer surface of the cortical
bone, the healing and incorporation of allografts is extremely slow
and limited. To enhance the biological performance of allografts,
herein, we report a novel and simple approach for engineering a periosteum
mimetic coating on the surface of structural bone allografts via polymer-mediated electrospray deposition. This approach
enables the coating on allografts with precisely controlled composition
and thickness. In addition, the periosteum mimetic coating can be
tailored to achieve desired drug release profiles by making use of
an appropriate biodegradable polymer or polymer blend. The efficacy
study in a murine segmental femoral bone defect model demonstrates
that the allograft coating composed of poly(lactic-co-glycolic acid) and bone morphogenetic protein-2 mimicking peptide
significantly improves allograft healing as evidenced by decreased
fibrotic tissue formation, increased periosteal bone formation, and
enhanced osseointegration. Taken together, this study provides a platform
technology for engineering a periosteum mimetic coating which can
greatly promote bone allograft healing. This technology could eventually
result in an off-the-shelf and multifunctional structural bone allograft
for highly effective repair and reconstruction of large segmental
bone defects. The technology can also be used to ameliorate the performance
of other medical implants by modifying their surfaces.
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