Methacrylic acid as functional monomer

A fluorescent MIP chemosensor for determination of 9-ethyladenine was fabricated [56]. It contained porphyrin as a luminescent functional monomer. The interaction of 9-ethyladenine with the porphyrin quenched the MIP luminescence at 605 nm when excited at 423 nm. The polymer was sensitive to 9-ethyladenine in the range of 0.01-0.1 mM however, it was already saturated at 0.15 mM. The same researchers used vinyl-substituted zinc(II) porphyrin and methacrylic acid as functional monomers for imprinting of (-)-cinchonidine [57]. The MIP luminescence, when excited at 404 nm, was significantly quenched at 604 nm upon binding of (-)-cinchonidine, even in the low concentration range of 0.01-2 mM. 

Chiral cation exchangers are rarely reported. However, the dominance of an ion-exchange retention model could be established by Sellergren and Shea for an acidic-imprint type CSP that was prepared from methacrylic acid as functional monomer and basic phenylalanine-anilide as oppo.sitely charged template, (1). 380. Maxima in retention were observed at pH-values close to the (apparent) pKa-value of the solutes... 

Fig. 34 Molecular imprinting of cinchonidine using zinc(ll)-porphyrin complex and methacrylic acid as functional monomers...

Sellergren [58] has used the same type of binding partners in a reverse manner, preparing pentamidine imprinted polymers for solid-phase extraction with methacrylic acid as functional monomer. Addition of an excess of acid to an isopropa-nolic, template containing polymerization mixture led to formation of a precipitate which was dissolved by adding water. 

Most of the water-soluble monomers, such as the acrylic and methacrylic acids, are functional monomers and are covered in Section 6.2.3. In Table 6.1 the most water-soluble monomers are acrylamide, acrylonitrile, methyl acrylate and vinyl acetate. Acrylamide contains two reactive centres. The amide group undergoes the reactions characteristic to aliphatic amides. For this reason, acrylamide may be considered as a functional monomer. Copolymerization of acrylamide with other monomers is often done to incorporate hydrophilic centres in oleophylic polymers to promote adhesion and dye acceptance. The monomer is available either as a solid or as a 50% aqueous solution. The latter is the preferred form, since it eliminates handling of a solid. The monomer is a neurotoxin and exposure to skin or inhalation must be prevented. Acrylamide solution is stabilized with cupric ions. Cupric ion availability is pH dependent and the pH must be between 5.2 and 6. Storage temperature should be between 16 and 32 °C... 

Monomers. A wide variety of monomers can be used, and they are chosen on the basis of cost and abiUty to impart specific properties to the final product. Water solubiUties of iadustriaHy important monomers are shown ia Table 1 (38). The solubiUty of the monomer ia water affects the physical chemistry of the polymerization. Functional monomers like methacrylic and acryUc acid, infinitely soluble ia water, are also used. These monomers impart long-term shelf stabiUty to latices by acting as emulsifiers. The polymerization behavior of some monomers, such as methacrylic acid, as well as the final latex properties are iafiuenced by pH. For optimum results with these acids, polymerization is best performed at a pH of ca 2. After polymerization, the latex is neutralized to give adequate shelf stabiUty at tractable viscosities. 

For this reaction, soluble monomers are needed, e.g. a mixture of N AT-methylene bisacrylamide as crosslinker, methacrylamide as an inert comonomer, methacrylic acid as ionic comonomer for stabilization [309] and methacryl ami-do-AT-acetaldehyde-dimethylacetal as functional comonomer. The coupling with proteins is only possible if the free aldehyde groups are accessible, i.e. if they are not located in the interior of the microgel. This condition can only be fulfilled by a careful choice of the comonomer composition in the reaction mixture [291]. 

An intriguing report by Steinke et al. [ 17] describes the creation of molecularly imprinted anisotropic polymer monoliths . Optically transparent blocks of MIP using either methacrylic acid (MAA) or 2-(acrylamido)-2-methylpropanesulphonic acid (AMPSA) as functional monomers and TRIM (trimethylolpropane trimethacrylate 2-ethyl-2-(hydroxymethyl)-l,3-propanediol trimethacrylate) as the cross-linker were synthesised using the photoactive template Michler s ketone... 

More recently, a diastereoselective molecularly imprinted fluorescent polymer for (-)-cinchonidine was prepared by the combined use of methacrylic acid and vinyl-substituted zinc(II) porphyrin monomer as functional monomers [24], Compared to the reference imprinted polymers using either MAA or zinc(II) porphyrin as a functional monomer, the imprinted polymer prepared with both MAA and the porphyrin... 

Figure 4 Representation of functional monomers that can serve as building blocks in noncovalent molecular imprinting. The first row represents acidic functional monomers with methacrylic acid as the most widely used functional monomer. In the second row, a selection of basic functional monomers is shown. Neutral monomers are lined up in the third row and the last row contains monomers that were designed and synthesized for a specific purpose. For example, 4-vinylbenzyl-iminodiacetic acid serves as a metal chelating monomer [89], methyl-a-D-glucopyranoside-6-acrylate was used in the imprinting of a protected amino acid [90]. As the last example, a monomer that would fluorescence upon rebinding of the template is depicted [91].

Recently, Takeuchi and coworkers [37] reported the use of molecular imprinting for constructing a highly specific porphyrin-based receptor site. 9-Ethyladenine [37] was chosen as the imprint molecule. Two different functional monomers were utilized to bind 58 during the polymerization process, methacrylic acid (MAA) and a polymerizable zinc-porphorin derivative, 59 (P-53), as shown in Fig. 20. Reference polymers imprinted with 56 were fabricated using either 59 or MAA (P-54 and P-55, respectively) and corresponding nonimprinted, blank polymers were prepared using MAA and 59, MAA, or 57 as functional monomers to form polymers P-56, P-57, and P-58, respectively (Fig. 21). 

Figure 21 Schematic representation of molecular imprinting of 9-ethyl adenine (9EA) using 5,10,15-tris(4-isopropylphenyl)-20-(4-methacyloloxyphenyl)porphyrin zinc (II) complex and methacrylic acid as a functional monomer.

An imprinted polymer for 5-propanolol was then grown from the surface, using methacrylic acid as the functional monomers and l,l,l-tris-(hydroxymethyl) propane trimethacrylate as the cross-linker, using toluene, dichloromethane, or acetonitrile as the porogenic solvent. The ability of the polymer-coated column to separate the R- and enantiomers of propanolol was investigated. Those polymers prepared in... 

The first publication in the area of CEC + MIP described the in situ preparation of MIP in capillaries by firstly activating a fused silica capillary with trimethoxysilyl-propyl methacrylate, followed by rinsing a mixture of ethyleneglycol dimethacrylate (EGDMA) as cross-linker, methacrylic acid (MA A) as functional monomer, azobis-(isobutyronitrile) (AIBN) as initiator, 2-propanol or cyclohexanol/dodecanol (4 1, v/v) as porogen, and L-phenylalanine anilide, pentamidine or benzamidine as template, through the capillary [29]. After polymerization at 60°C, the polymer within the capillary was washed with ethanol and finally dried. Samples of the analytes used... 

Figure 12 Molecular imprinting of (i )-propranolol using methacrylic acid (MAA) as functional monomer and trimethylolpropane trimethacrylate (TRIM) as cross-linker. Since the imprinted enantiomer possesses the higher affinity for the polymer, in the electrochromatogram the ( S )-propranolol occurs first, and (R)-propranolol appears as the longer retarded analyte, i.e., as the second and broader peak. (From Ref. 32.)...

Imprinted polymer membranes are prepared using atrazine as the template, methacrylic acid as a functional monomer, and tri(ethylene glycol) dimethacrylate (TEDMA) as a cross-linker. The molar ratio of the functional monomer to the template is 5 1. This ratio has to be optimized for each template. In order to obtain thin, flexible and mechanically stable membranes, oligourethane acrylate (molecular mass 2600) is added to the monomer mixture. Preparation of the molecularly imprinted polymer membrane is done as follows. Atrazine (20 mg) is mixed with methacrylic acid (40 mg), TEDMA (289 mg), oligourethane acrylate (51 mg), AIBN (2 mg) and 30% v/v of chloroform. Then a 60-120 pm gap between two quartz slides is filled with the monomer mixture. To initiate polymerization, the slides with the mixture are exposed to UV radiation (365 nm, intensity 20 W m ) for 30 min. After polymerization, atrazine is extracted with ethanol in a Soxhlet apparatus for 2h. This should not cause any visible changes in the MIP membrane. A membrane for control experiments can be prepared similarly except that no atrazine is added to the monomer mixture. 

Here we report on the syntheses and characterization of functional graftcopolymers by the macromonomer technique. Hydrophobic perfluoroalkyl acrylate and hydrophilic mathacrylic acid or 2-hydroxyethyl methacrylate (HEMA) was chosen as functional monomers to modifity the polymer surfaces. For the purpose of surface accumulation stearyl (SMA) or lauryl methacrylate (LMA) was used besides perfluoroalkyl acrylate(FA) to constitute surface active segments. Methyl methacrylate (MMA) and styrene (St) was used to form the principal constituent. 

By a surface imprinting technique, in Zhang H. et al., 2011, a comfX)site imprinted material, on the basis of a MWCNTs-incorporated layer using melamine as a template, methacrylic acid as a functional monomer, and ethylene glycol dimethaciylate as a cross-linker, was synthesized. In this work, the poly(acrylic-acid)-functionalized CNTs were synthesized to increase the diameter of CNTs. Then, the vinyl group was introduced to the surface of poly(acrylic-acid)-functionalized CNTs by an amidation Using Melamine as a template molecule, imprinted CNT composite material was fabricated by a thermal fX)lymeiization. Applied as a sorbent, the imprinted materials were used for the determination of Melamine in the spiked sample by online SPE combined with HPLC. 

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