Antibiotic Zwitterionic Nanogel Membrane: from Molecular Dynamics Simulation to Structure Manipulation

Membrane separation has been considered as one of the most revolutionary technologies for the removal of oils, dyes, or other pollutants from wastewater. However, most membranes still face great challenges in water permeability, antifouling property, and even antibiotic ability. Possessing a pathogen-repellent surface is of great significance as it can enable membranes to minimize the presence of active viral pathogens. Herein, we demonstrate a distinct design with a molecular dynamics simulation-guided experiment for the surface domination of antibiotic zwitterionic nanogel membranes. The zwitterionic nanoparticle gel (ZNG)/Cu²⁺/glutaraldehyde (GA) synergy system is first simulated by introducing a ZNG into a preset CuCl₂ brine solution and into a GA ethanol solution, in which the nanogel is observed to initially swell and subsequently shrink with the increase of GA concentration, leading to the membrane surface structure transition. Then, the corresponding experiments are performed under strict conditions, and the results suggest the surface structure transition from nanoparticles to network nanoflowers, which are consistent with the simulated results. The obtained network structure membrane with superhydrophilic and underwater superoleophobic abilities can significantly enhance the water permeability as high as almost 40% with its original rejection rate in comparison with unoptimizable ZNG-PVDF (polyvinylidene difluoride) membranes. Moreover, the obtained membrane achieves additional excellent antibiofouling capacity with the antibiotic efficiency exceeding 99.3%, manifesting remarkable potential for disinfection applications. By comparison, the conventional antibiotic methods generally improve the membrane's antibiotic property solely but can hardly improve the other properties of the membrane. That is to say, our simulation combined with the experimental strategy significantly improved the zwitterionic membrane property in this work, which provides a new perspective on the design of high-performance functional materials.