Journal of Colloid and Interface Science最新文献

It is commonly recognized that hydrophilic surfaces reduce protein membrane adhesion during aqueous bioprocessing due to water's strong binding through electrostatic and hydrogen bonding capability. Here, we show that when (i) a protein displaces bound water at a polymer interface, hydrogen bonding and electrostatic interactions with the polymer membrane surface drive protein adhesion, and (ii) comparing two commonly used commercial hydrophilic polymer membranes with different polar surface modification chemistries, the one with higher hydrogen bonding capability (modified polyethersulfone (mPES)) exhibited three times higher adhesion force to a hydrophilic protein (streptavidin) than the one with lower hydrogen bonding capability (modified polyvinylidene fluoride (mPVDF)). Stronger protein-membrane hydrogen bonding for mPES as corroborated by its higher electron donor surface energy component and higher hydrogen bonding propensity observed from surface energy measurements and by solvation shell spectroscopy, respectively, support our explanation of these results. Atomic force microscopy (AFM) colloid probe technique was used here to measure intermolecular forces/energy between streptavidin and two polymeric membrane surfaces. Non-contact forces at separations greater than 2 nm were modeled using the DLVO theory, while contact/adhesion forces, which include hydrogen bonding, were measured at separation ∼0.16 nm. These findings highlight the importance of protein-polymer membrane hydrogen bonding interactions in selecting polymers for membrane downstream purification and other applications.

Vanadium flow batteries (VFBs), as a high-safety grid-scale energy storage technology, provide an ideal solution for storing green power generated from intermittent renewable energy sources. However, the sluggish kinetics of the V³⁺/V²⁺ redox reaction at the negative electrode interface limits the development of VFBs toward high-rate performance. Herein, density functional theory (DFT) calculations demonstrate the feasibility of phosphorus (P) atom modulation on the electronic structure at the N, O dual-doped carbon interface. Afterwards, P-modulated polybenzimidazole (PBI)-derived N, O-rich composite electrodes are fabricated via a loading-calcination strategy. The introduction of P atom enhances the adsorption of vanadium ion at the interface and improves the p-d orbital coupling between the electrode and vanadium ion. The VFB with the modified electrode shows an energy efficiency (EE) of 82.27 % at 150 mA cm^-2 and maintains stable cycling performance with only 2.4 % EE decay after 2000 cycles at 100 mA cm^-2. This electronic structure modulation strategy provides new insights into the development of next-generation high-performance and long-life VFBs.

Modified TiO₂ photocatalysts face challenges dependence on cocatalysts, weak interfacial interactions, and poor wettability. This work presents an effective strategy by coupling donor-donor (D-D) type cationic conjugated polyelectrolyte poly[(9,9-bis(3'-((N,N-dimethyl)-N-ethylammonium)-propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)]dibromide (PFN-Br) with two-dimensional TiO₂ (2D-TiO₂) nanosheets to construct type-II heterojunctions rich in active sites. Under optimal conditions, the 2D-TiO₂/50 wt% PFN-Br (2D-Ti/PBr-50) heterojunction achieved a hydrogen evolution reaction of 2621.01 μmol g^-1 h^-1 without any cocatalyst-representing 21.86 times higher than that of pristine 2D-TiO₂ nanosheets. This significant enhancement is mainly attributed to the strong visible-light absorption capability of PFN-Br, well-matched band alignment with 2D-TiO₂ nanosheets, reinforced interfacial interactions via hydrogen bonding and electrostatic forces, the porous nanostructure of the 2D-Ti/PBr heterojunction, and good interfacial wettability due to the ionic side chains of PFN-Br. This study offers new insights into polyelectrolyte-assisted TiO₂ photocatalysts for cocatalyst-free applications.