Facile Preparation of Core−Shell Type Molecularly Imprinted Particles:  Molecular Imprinting into Aromatic Polyimide Coated on Silica Spheres

Abstract

Core-shell type imprinted spherical particles were prepared by using a conventional polymer solution coating method. A poly(amic acid) was synthesized by step-reaction polymerization of the diamines (1:19 mole ratio of the diamine monomer-template complex:4,4′-oxydianiline) and the pyromellitic dianhydride in N,N-dimethylacetamide at ambient temperature. The diamine monomer-template complex was synthesized by the reaction of the diamine having an isocyanato group and estrone (template) having a phenol moiety, in which the template was connected to the monomer by means of a thermally reversible urethane bond. The poly(amic acid) containing the template (estrone) molecule was used for the coating of a silica sphere, of which surface was functionalized with amino groups to increase the adhesion property of the poly(amic acid) film on the silica. The thermal imidization resulted in a spherical silica particle coated with a polyimide (thickness of polyimide: about 100 nm). The template molecules were removed from the polyimide layer by heating the particles in 1,4-dioxane in the presence of water or aniline. In the process, the isocyanato groups, which were generated by dissociation of thermally reversible urethane bonds, were converted to amino or phenyl urea groups by the reaction with water or aniline, respectively. The imprinted silica particles were used as a stationary phase in HPLC mode and their specific recognition ability for estrone and its structural analogues were evaluated.

Use of Templates to Fabricate Nanoscale Spherical Structures for Defined Architectural Control

“…Lvov and co‐workers have also reported the self‐assembly of tannic acid with strong and weak polycations and produced capsules with the lowest permeability at pH 5–7 78. Many other polymers have also been used to create the shell layer, such as PMAA by Caruso et al,51 Wortman et al,53 and Sukhishvili et al,77 polyvinylamine by Shi et al,79 polyimide by Chang and co‐workers,80 and polyalanine (PANI) and polypyrrole by Yang et al6 and Oh and co‐workers 14…”

In situ preparation and characterization of polyimide/silica composite hemispheres by inverse aqueous emulsion technique and sol-gel method

“…PI/inorganic composite materials have combined the special structure of inorganic component and excellent properties of PI and have become a type of promising materials focused on various applications [27][28][29]. In the past years, a number of researches have been carried out on the preparation and characterization of homogeneous polyimide-silica composite materials [30][31][32][33][34][35][36][37][38][39]. Most of them focused on the preparation of homogeneous PI/SiO 2 hybrid films via the sol-gel process.…”

“…The transmission electron microscopy (TEM) image showed that SiO 2 was surfacecoated in PI and the PI/SiO 2 nanocomposite particles were core-shell structure. Kim [39] successfully fabricated coreshell-type molecularly imprinted spherical particles by using a conventional polymer solution coating method. A poly(amic acid) was used for the coating of a silica sphere and converted to the polyimide layer, which had a rigid structure suitable for molecular imprinting.…”

Synthesis and characterization of vinyl‐functionalized multiwalled carbon nanotubes based molecular imprinted polymer for the separation of chlorpyrifos from aqueous solutions

“…To avoid these troubles, core shell structural MIPs have been introduced recently . A thin layer of MIPs was polymerized on top of some solid chains, such as monodispersed polystyrene seeds, silica and carbon nanotubes.…”