RESUMEN
Zwitterionic materials have received great attention because of the non-fouling property. As a result of the electric neutrality of zwitterionic polymers, their layer-by-layer (LBL) assembly is generally conducted under specific conditions, such as very low pH values or ionic strength. The formed multilayers are unstable at high pH or in a high ionic strength environment. Therefore, the formation of highly stable multilayers of zwitterionic polymers via the LBL assembly process is still challenging. Here, we report the LBL assembly of poly(sulfobetaine methacrylate) (PSBMA) with a polyphenol, tannic acid (TA), for protein-resistant surfaces. The assembly process was monitored by a quartz crystal microbalance (QCM) and variable-angle spectroscopic ellipsometry (VASE), which confirms the formation of thin multilayer films. We found that the (TA/PSBMA)n multilayers are stable over a wide pH range of 4-10 and in saline, such as 1 M NaCl or urea solution. The surface morphology and chemical composition were characterized by specular reflectance Fourier transform infrared spectroscopy (FTIR/SR), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). Furthermore, (TA/PSBMA)n multilayers show high hydrophilicity, with a water contact angle lower than 15°. A QCM was used to record the dynamic protein adsorption process. Adsorption amounts of bovine serum albumin (BSA), lysozyme (Lys), and hemoglobin (Hgb) on (TA/PSBMA)20 multilayers decreased to 0.42, 52.9, and 37.9 ng/cm(2) from 328, 357, and 509 ng/cm(2) on a bare gold chip surface, respectively. In addition, the protein-resistance property depends upon the outmost layer. This work provides new insights into the LBL assembly of zwitterionic polymers.
Asunto(s)
Metacrilatos/química , Taninos/química , Adsorción , Materiales Biocompatibles/química , Hemoglobinas/química , Microscopía de Fuerza Atómica , Muramidasa/química , Espectroscopía de Fotoelectrones , Tecnicas de Microbalanza del Cristal de Cuarzo , Albúmina Sérica Bovina/química , Espectroscopía Infrarroja por Transformada de Fourier , Propiedades de SuperficieRESUMEN
Silica-decorated polypropylene microfiltration membranes were fabricated via a facile biomimetic silicification process on the polydopamine/polyethylenimine-modified surfaces. The membranes exhibit superhydrophilicity and underwater superoleophobicity derived from the inherent hydrophilicity and the well-defined micronanocomposite structures of the silica-decorated surfaces. They can be applied in varieties of oil-in-water emulsions separation with high permeate flux (above 1200 L/m(2)h under 0.04 MPa) and oil rejection (above 99%). The membranes also have relatively high oil breakthrough pressure reaching 0.16 MPa due to the microporous structure, showing great potential for practical applications. Furthermore, such mussel-inspired intermediate layer provides us a convenient and powerful tool to fabricate organic-inorganic hybrid membranes for advanced applications.
Asunto(s)
Bivalvos/química , Membranas Artificiales , Aceites/química , Polipropilenos/química , Dióxido de Silicio/química , Ultrafiltración/métodos , Agua/química , Animales , Emulsiones , Indoles/química , Permeabilidad , Espectroscopía de Fotoelectrones , Polietileneimina/química , Polímeros/químicaRESUMEN
We report a simple and facile protocol to fabricate mussel-inspired polydopamine (PDA) gradients on different surfaces. An oxygen diffusion phenomenon was used for dopamine autoxidation to form thickness gradients of PDA on different substrates. These PDA gradients showed gradual changes in thickness, roughness, wettability and light transmittance.