Functional monomers interactions

In the following years, many imprinted polymers were prepared by two- or multi-step swelling and polymerisation method using mostly EDMA as a crosslinker and various functional monomers interacting with the chosen template... 

Note that with chiral guest molecules for which it is difficult to obtain a pure enantiomer, the use of a chiral functional monomer, interacting preferentially with one of the two enantiomers in a racemic mixture, can be an interesting approach [45]. 

It should be noted that spectroscopic titration usually shows the formation of a 1 1 adduct between template and functional monomer, even when several functional monomers interact with several parts of template. In other words, these interactions are almost independent of each other in solutions (n 1 monomer/template complexes are hardly formed therein because of the unfavorable entropy term). Even in these cases, the monomers which are interacting with the template at different positions are covalently bound to each other in the polymerization. These steps should proceed in a stepwise manner. Thus, the polymerization occurs around a site of the template. Independently, polymers are also formed at other sites of the template. Finally, these polymer do-... 

The number and relative strengths of different template-functional monomer interactions, as given by the term, dictate the degree of selectivity of the resultant... 

We use the off-lattice MC model described in Sec. IIB 2 with a square-well attractive potential at the wall, Eq. (10), and try to clarify the dynamic properties of the chains in this regime as a function of chain length and the strength of wall-monomer interaction. 

Fig. 6-10. Influence of the number of basic interaction sites of the template versus the separation factor measured in chromatography for the corresponding racemate. The templates were imprinted using MAA as functional monomer by thermochemical initiation at 60/90/120 °C (24 h at each temperature) and using acetonitrile as porogen. (From Sellergren et al. [15].)...

Figure 21-2. Fatty acid synthase multienzyme complex. The complex is a dimer of two identical polypeptide monomers, 1 and 2, each consisting of seven enzyme activities and the acyl carrier protein (ACP). (Cys— SH, cysteine thiol.) The— SH of the 4 -phosphopantetheine of one monomer is in close proximity to the— SH of the cysteine residue of the ketoacyl synthase of the other monomer, suggesting a "head-to-tail" arrangement of the two monomers. Though each monomer contains all the partial activities of the reaction sequence, the actual functional unit consists of one-half of one monomer interacting with the complementary half of the other. Thus, two acyl chains are produced simultaneously. The sequence of the enzymes in each monomer is based on Wakil.

Molecular imprinting can be accomplished in two ways (a), the self assembly approach and (b), the preorganisation approach3. The first involves host guest complexes produced from weak intermolecular interactions (such as ionic or hydrophobic interaction, hydrogen bonding) between the analyte molecule and the functional monomers. The self assembled complexes are spontaneously formed in the liquid phase and are sterically fixed by polymerisation. After extraction of the analyte, vacant recognition sites specific for the imprint are established. Monomers used for self assembly are methacrylic acid, vinylpyridine and dimethylamino methacrylate. 

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