title: Surface molecular imprinted layer-by-layer film attached to a porous membrane for selective filtration.
abstract: A surface molecular imprinted layer-by-layer (SMILbL) film was fabricated on a polyethersulfone (PES) porous membrane substrate for selective filtration of cations and anions. The LbL deposition procedure and the ultraviolet (UV) cross-linking of the modified membrane were monitored by attenuated total reflection-infrared (ATR-IR) spectra. The SMILbL-PES membrane with 4.5 bilayers of diazoresin (DAR)/poly(acrylic acid) complexed with 5,10,15,20-tetrakis(4-(trimethylammonio)-phenyl)-21H,23H-porphyrin tetratosylate (PAA-Por(4+)) effectively reduced the permeation velocity of Por(4+) after washing the Por(4+) template out. In comparison to a control film DAR/PAA-modified PES membrane (ConLbL-PES) in a dialysis experiment, the SMILbL-PES membrane exhibited better selectivity for permeation of 5,10,15,20-tetraphenyl-21H,23H-porphine-p,p',p″,p‴-tetrasulfonic acid tetrasodium hydrate (Por(4-)) against permeation of Por(4+). In pressure-driven transport experiments, the SMILbL-PES membrane showed a much longer blocking time for Por(4+) than for Por(4-), indicating the selective loading of Por(4+) into the SMILbL film. The surface charge of the SMILbL-PES membrane after Por(4+) loading was higher than that of other membranes, resulting in an enhanced rejection ability of the SMILbL-PES membrane to Por(4+) caused by Coulomb repulsion. A possible mechanism was proposed as follows. The binding sites generated through imprinting in the SMILbL-PES membrane enable loading of a larger amount of Por(4+). The stronger repulsion between Por(4+) and the SMILbL film may cause the main contribution to the selective rejection of Por(4+). It can be easily imagined that this concept can be extended to the construction of composite membranes from other imprinting systems.
authors.affiliation: Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100090, People's Republic of China.
authors.forename: Zhihua
authors.initials: Z
authors.lastname: Liu
authors.forename: Yu
authors.initials: Y
authors.lastname: Yi
authors.forename: Jan
authors.initials: J
authors.lastname: Gauczinski
authors.forename: Huaping
authors.initials: H
authors.lastname: Xu
authors.forename: Monika
authors.initials: M
authors.lastname: Schönhoff
authors.forename: Xi
authors.initials: X
authors.lastname: Zhang
mesh_terms: D008567:Membranes, Artificial; D054802:Molecular Imprinting; D015394:Molecular Structure; D010316:Particle Size; D011108:Polymers / Q000737:chemistry*; D016062:Porosity; D013450:Sulfones / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D008567:Membranes, Artificial; D011108:Polymers; D013450:Sulfones; C022840:polyether sulfone