Polyanion cluster patterning on polymer surface through microemulsion approach for selective adsorption of proteins

A facile method to fabricate honeycomb-patterned polymer films bearing cavities that are locally decorated with inorganic component is developed in this study. By mixing poly(methyl methacrylate) dichloromethane solution containing P123 with polyoxometalate (POM) aqueous solution through shaking, a reversed hybrid microemulsion is obtained. The evaporation of solvent in the microemulsion on solid surface yields an ordered porous film accompanied by the accumulation of P123 and POMs on the inner surface of the cavities. The formation of patterned structure is proved to be independent from the type of POMs, but the size of the cavities can be adjusted to some extent by changing the concentration of surfactant and polymer, and the volume ratio of water and dichloromethane in the solution used for casting. The locally anchored POMs can be readily applied for the selective recognition of proteins. BSA and hemoglobin patterns are then fabricated through their electrostatic interactions with POMs. At lower pH, POM pattern could prior recognize hemoglobin from its mixed solution of BSA, generating a characteristic pattern. The reported work creates an efficient way of patterning organically incompatible components, such as water-soluble molecules and nanoparticles, on porous polymer films for the fabrication of multi-functional hybrid surface structures.