Surface functionalized porous polymers

Figure 4,9. Different types of polymer particles for liquid chromatography. Macroporous polymer (A), surface functionalized porous polymer for cation-exchange chromatography (B) and electrostatically agglomerated anion-exchange particle (C).

The restricted access principle is based on the concept of diffusion-based exclusion of matrix components and allows peptides, which are able to access the internal surface of the particle, to interact with a functionalized surface (Figure 9.2). The diffusion barrier can be accomplished in two ways (i) the porous adsorbent particles have a topochemically different surface functionalization between the outer particle surface and the internal surface. The diffusion barrier is then determined by an entropy controlled size exclusion mechanism of the particle depending on the pore size of adsorbent (Pinkerton, 1991) and (ii) the diffusion barrier is accomplished by a dense hydrophilic polymer layer with a given network size over the essentially functionalized surface. In other words, the diffusion barrier is moved as a layer to the interfacial... 

Another approach is similar to that used in for the preparation of polymer-layer open tubular GC columns (PLOT). Horvath s group prepared capillaries with a porous polymer layer as shown in Fig. 13 by in situ polymerization of vinylbenzylchloride and divinylbenzene [183]. The reaction of the N,N-di-methyldodecylamine with chloromethyl groups at the surface simultaneously afforded strong positively charged quaternary ammonium functionalities and attachment of C12 alkyl chains to the surface. The unreacted chloromethyl groups... 

Piletsky SA, Matuschewski H, Schedler U, Wilpert A, Piletska EV, Thiele TA, Ulbricht M. Surface functionalization of porous polypropylene membranes with molecularly imprinted polymers by photograft copolymerization in water. Macromolecules 2000 33 3092-3098. 

This study is devoted to the investigation of porous methacrylate polymeric systems filled with chemically modified fumed silicas. IR and 13C NMR spectroscopies combined with AFM was applied to characterize changes in the material structure, and also the effect of surface functional groups of inorganic particles on the polymer-filler interaction. 

The synthesis of phenolic-formaldehyde and melamine-formaldehyde resins in the presence of fumed silica allows obtaining porous organic materials with a differentiated porous structure and surface properties. The pore characteristics of the studied resins in dry state were determined from nitrogen adsorption isotherms. The differences in surface character of the synthesized polymers were estimated satisfactorily by XPS spectra showing the presence of various functional groups. The adsorption/desorption mechanism of water and benzene on the investigated porous polymers was different due to differentiated hydrophobicity of the bulk material. 

Organic polymers are functionalized directly at their surface, with the exception of latex-based anion exchangers (see Section 3.3.1.2), where the totally porous latex particle acts as ion-exchange material. Surface-functionalized, pellicular substrates show a much higher chromatographic efficiency compared to the fully functionalized resins. The organic polymers mentioned above are functionalized in a two-step process ... 

Porous polymer spheres with a range of diameters, pore sizes, and composition (or surface functionality) can be purchased. Antonietti et al. have shown that porous polymer spheres could be cast to form monolithic materials [33]. Water-... 

The key to repeated use is the coexistence of hydrophilic groups and functional groups. The surface of protein has hydrophobic patches. Therefore, proteins easily adsorb nonselectively onto the surface of a hydrophobic polymeric support. In order to realize repeated adsorption and elution of protein using functional porous membranes, alcoholic hydroxyl groups are appended along with the functional groups of the polymer chains grafted onto the pore surface. This idea is similar to that on which Svec s work [68] was based. 

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