Preparation and characterization of magnetic molecularly imprinted polymers for selective recognition of 3‐methylindole

In this work, magnetic molecularly imprinted polymers (MMIPs) were used as novel adsorbents for selective adsorption of 3‐methylindole from model oil. The MMIPs were synthesized by precipitation polymerization and surface molecularly imprinted technique, using Fe₃O₄ nanoparticles as magnetically susceptible component, methylacrylic acid as dressing agent and functional monomer, ethylene glycol dimethacrylate as crosslinker, and 3‐methylindole as template molecule. The MMIPs were characterized by Fourier‐transform infrared spectroscopy, scanning electron microscopy, vibrating sample magnetometer, and thermogravimetric analyzer, respectively. The adsorption performances of MMIPs were investigated by batch adsorption experiments in terms of kinetics, isotherms, and selective recognition adsorption, respectively. The results indicate that MMIPs have high recognition ability and fast binding kinetics for 3‐methylindole. Meanwhile, the adsorption equilibrium time was about 2 h and the equilibrium adsorption amount was ～38 mg g^?1 at 298 K. The heterogeneous MMIPs were modeled with pseudo‐second‐order and Langmuir isotherm equation. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2859–2866, 2013     

Preparation and characteristics of a dummy molecularly imprinted polymer for phenol

A dummy molecularly imprinted polymers (DMIP) for phenol was synthesized by a thermal polymerization method with acrylamide as the functional monomer, ethylene dimethacrylate as the crosslinker, 2,2‐azobisisobutyronitrile as the free‐radical initiator, acetonitrile as the porogenic solvent, and sulfadiazine, a phenol analogue, as the template. In comparison to other adsorbents, the synthesized DMIP showed a higher capacity and rate of adsorption. The adsorption amount of the DMIP adsorbents for phenol reached 6.09 ± 0.15 mg/g, and the adsorption rate of the DMIP was about 0.406 ± 0.01 mg g^?1·min^?1. The results indicate that the Freundlich model fit the adsorption model of DMIP for phenol. The adsorption model of DMIP for phenol was multilayer adsorption. This showed that the DMIP synthesized by bulk polymerization could be used as a novel adsorbent for the removal of phenol from contaminated water. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Preparation of molecularly imprinted polymer coatings with the multiple bulk copolymerization method for solid‐phase microextraction

The multiple bulk copolymerization method, which was developed in our previous works, was further investigated with prometryn, tetracycline, and propranolol as templates for the preparation of molecularly imprinted polymer (MIP) coatings on silicon fibers for solid‐phase microextraction. The preparation conditions (e.g., the solvent, monomer, crosslinker, component proportions, polymerization time, and number of coating procedures) were investigated systemically in an effort to enhance the coating thickness, surface morphology, and reproducibility. The methodology was examined, and some common specialties were explored in the preparation of three MIP‐coated fibers. Even after the coating procedure was repeated 10 times, the prometryn, tetracycline, and propranolol MIP‐coated fibers were prepared reproducibly with coating‐thickness relative standard deviations of 2.6, 3.0, and 5.1%, respectively; they were highly homogeneous, and a compact morphological structure was obtained. The extraction capacities of prometryn, tetracycline, and propranolol with corresponding MIP‐coated fibers were approximately 10.4, 3.9, and 3.3 times as much as those with the nonimprinted polymer (NIP)‐coated fibers, respectively, and the selectivity factors of prometryn, tetracycline, and propranolol MIP coatings for the template molecules and structural analogues were 2.2–10.4, 2.2–3.9, and 1.3–3.3, respectively, in comparison with the corresponding NIP coatings. In comparison with commercial polydimethylsiloxane/divinylbenzene coatings that were approximately 3 times thicker, the extracted amounts of prometryn, tetracycline, and propranolol were 4.2, 12.3, and 7.7 times higher with prometryn, tetracycline, and propranolol MIP coatings, respectively. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Preparation of molecularly imprinted polymers in supercritical carbon dioxide

Molecularly imprinted polymer nanoparticles were prepared in supercritical carbon dioxide using a noncovalent imprinting approach. In the present work, propranolol was used as a model template, methacrylic acid as a functional monomer, and divinylbenzene as a crosslinker. Under a high dilution condition, the heterogeneous polymerization resulted in discrete crosslinked polymer nanoparticles. Compared with the nonimprinted polymers, the imprinted nanoparticles displayed much higher propranolol uptake in a low polarity organic solvent. The use of a single enantiomer (S)‐propranolol as the template clearly demonstrated that the imprinted binding sites are chiral‐selective, with a cross‐reactivity towards (R)‐propranolol of less than 5%. The overall binding performance of the imprinted nanoparticles was comparable to imprinted polymers prepared in conventional organic solvents. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2863–2867, 2006     

Water‐compatible imprinted polymers based on CS@SiO2 particles for selective recognition of naringin

Molecularly imprinted polymers are being proposed for the development of novel biorecognition elements for active components. In this study, an imprinted chitosan coated silica nanoparticles (I‐CS@SiO₂) polymer was prepared by a simple procedure, in which, naringin (NG) with antioxidant activity, acted as a template, silica as a matrix and CS as a functional polymer. The binding properties were discussed by the equilibrium binding experiment method. Experiments show that the adsorption characteristics of I‐CS@SiO₂ are better than that of nonimprinted polymer. It exhibited high selectivity for NG when compared with the nonimprinted polymer, with an imprinting factor α of 1.74. Scatchard analysis of the I‐CS@SiO₂ indicated that there was a class of binding sites during the I‐CS@SiO₂ recognizing NG: The dissociation constant of K_D is 0.016 mmol L^?1, the maximum apparent binding capacity of B_max is 6.56 μmol g^?1. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40491.     

Uniform‐sized clenbuterol molecularly imprinted polymers prepared with methacrylic acid or acrylamide as an interacting monomer

Clenbuterol molecularly imprinted polymer microbeads were prepared with a two‐step swelling and thermal polymerization technique with either methacrylic acid or acrylamide (AAm) as the monomer and ethylene glycol dimethacrylate as the crosslinker at different monomer/crosslinker ratios. The quality of the microbeads, in terms of shape, size distribution, rigidity, and monomer incorporation, was evaluated as a function of the reaction parameters. A good imprinting effect was obtained with both systems, as assessed by high‐performance liquid chromatography (HPLC) experiments with phosphate‐buffered saline/acetonitrile eluents, with a complete baseline separation of clenbuterol with respect to other β‐adrenergic agents obtained. When AAm was used as the monomer, improved control of the polymerization process was achieved, producing microbeads with lower polydispersity and no lack of separation capacity. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2660–2668, 2002     

Preparation of molecularly imprinted polymers for vanillin via reversible addition‐fragmentation chain transfer suspension polymerization

Molecularly imprinted polymers (MIPs) for vanillin were synthesized by suspension polymerization using ethylene glycol dimethacrylate as cross‐linker and methacrylic acid as functional monomer, respectively. The analysis of scanning electron microscopy and equilibrium binding experiments indicated that the MIPs can selectively separate the target analytes. Reversible addition‐fragmentation chain‐transfer (RAFT) technique was used to synthesize MIPs using benzyl dithiobenzoate as RAFT agent. The results showed smaller particle size, higher molecular adsorption, and considerable binding specificity toward vanillin than those prepared by suspension polymerization. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

基于壳聚糖的分子印迹聚合物的制备和应用

壳聚糖具有良好的生物相容性和独特的分子结构,基于其制备的分子印迹聚合物因亲和性和选择性高、应用范围广等特点引起了广泛的关注。本文首先总结了壳聚糖和改性壳聚糖在分子印迹聚合物制备中的作用,然后介绍了壳聚糖分子印迹聚合物在环境污染治理、医药、蛋白质分离与识别、手性物质分离以及吸附功能成分等方面的应用,分析了壳聚糖分子印迹聚合物在各个应用领域的优缺点及发展方向。最后,从发展绿色分子印迹技术以及分子印迹技术与电化学传感器结合等层面对壳聚糖分子印迹聚合物的应用前景进行了展望。     

Influence of template/functional monomer/cross‐linking monomer ratio on particle size and binding properties of molecularly imprinted nanoparticles

A series of molecularly imprinted polymer nanoparticles have been synthesized employing various template/functional monomer/crosslinking monomer ratio and characterized in detail to elucidate the correlation between the synthetic conditions used and the properties (e.g., particle size and template binding properties) of the obtained nanoparticles. In brief, the presence of propranolol (template) in the polymerization mixture turned out to be a critical factor on determination of the size as well as the binding properties of the imprinted nanoparticles. The functional monomer/crosslinking monomer ratio significantly affects the binding capability of the imprinted nanoparticles, but its influence on the size of the nanoparticles was found to be rather limited. The results obtained provide valuable clues for designing molecularly imprinted nanoparticle preparation in future studies, where fine tuning of particle size and binding properties are required to fit practical applications. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Preparation of ordered macroporous cinchonine molecularly imprinted polymers and comparative study of their structure and binding properties with traditional bulk molecularly imprinted polymers

Three‐dimensionally ordered macroporous molecularly imprinted polymers (MMIPs) were prepared by a combination of the colloidal crystal template method and the molecular imprinting technique. Traditional bulk molecularly imprinted polymers (BMIPs) were simultaneously synthesized with the same recipe as the MMIPs by using methacrylic acid as functional monomer, ethylene glycol dimethacrylate as crosslinker and chloroform as porogen. SEM and Brunauer ? Emmett ? Teller measurements show that MMIPs have a more regular macroporous structure, a narrower macropore distribution and a greater surface area and porosity compared with BMIPs. The isothermal and kinetic data of both polymers can be fitted with the Freundlich model and a pseudo‐second‐order equation, respectively. Their specificities to the template molecules are also similar. However, the binding capability, adsorption rate coefficient and internal effective diffusion coefficient of the MMIPs are higher than for the BMIPs when the particle size is above 54 µm. © 2015 Society of Chemical Industry     

Preparation of molecularly imprinted polymer films on monodisperse macromolecular beads

A new and facile technique for preparing homogeneous and highly selective molecularly imprinted polymers (MIPs) films on porous monodisperse poly‐(glycidyl methacrylate‐co‐ethylene glycol dimethacrylate) beads (P_GMA‐EDMA beads) has been described: before polymerization, initiator was immobilized on the P_GMA‐EDMA beads' surface by chemical reactivity; then functional monomers and crosslinkers were initiated by the surface‐bound initiator and copolymerized to form MIPs films on the P_GMA‐EDMA beads' surface in the presence of template molecules. The resulting beads were analyzed by FTIR spectroscopy and X‐ray photoelectron spectra. The effects of the initiator amount and copolymerization time on the content of MIPs, and MIPs contents on morphologies and pore properties of the resulting beads were investigated. The results show that the content of MIPs can be adjusted by changing initiator amount or by controlling copolymerization time. The binding experiments indicate that, at lower grafting level, with the increase of MIPs content, the adsorption and recognition capabilities of the resulting beads enhance. When MIPs content increase to 16.75%, the highest adsorption and recognition capabilities are obtained. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation of molecularly imprinted polymers: Diethyl(3‐methylureido)(phenyl)methylphosphonate as a dummy template for the recognition of its organophosphate pesticide analogs

A novel compound, diethyl(3‐methylureido)(phenyl)methylphosphonate (DEP), possessing an organophosphate skeleton, was synthesized and used as a dummy template to prepare molecularly imprinted polymers (MIPs) for the recognition of organophosphate pesticide analogs. Computational modeling was used to study the primary intermolecular interactions in the prepolymerization mixture. It was found that the interaction force between DEP and the monomers was hydrogen bonding. A series of MIPs were synthesized with different monomers and were evaluated by adsorption experiments, which showed that methacrylic acid was used as an appropriate monomer and a molar ratio of DEP to MAA of 1 : 9 was optimal. Scatchard analysis showed that there might have been two types of binding sites in the MIPs. DEP and several pesticides were used in molecular recognition specificity tests of DEP–MIP, which exhibited better selectivity and reservation ability for organophosphate pesticides, such as methamidophos and orthene, possessing amino or imino groups and a smaller steric hindrance. On the basis of the use of a dummy molecule as template, the problem of template leakage could be avoided; this, thereby, improved the specificity of analysis. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Preparation and adsorption selectivity of rutin molecularly imprinted polymers

Molecularly imprinted polymer (MIP) for Rutin had been prepared through solution polymerization by redox initiation. The effects of monomers, crosslinker, initiators, polymerization time, and temperature on adsorption selectivity for Rutin were investigated and optimized. The structure and surface morphology of MIP were evaluated by Fourier transform infrared spectroscopy and scanning electron microscopy, respectively. The synthesized MIP under the optimal conditions showed a specific recognition of Rutin from the mixture of Rutin and Isorhamnetin. And the maximal separation degree of Rutin was 5.0. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Using molecularly imprinted polymer for protecting functional group in organic reaction

In this study, a novel method of selective protecting group based on molecularly imprinted polymer for regioselective organic reaction is reported. The simplicity, convenience and feasibility of this method may be illustrated by the protection of hydroxyl group at C17 or C3 of β‐estradiol in the reaction between β‐estradiol and diphenylphosphinic chloride. Polymers to protect hydroxyl group at C17 or at C3, both demonstrated excellent protection effect. In polymers imprinted with 2‐methyl‐cyclopentanol template to protect hydroxyl group at C17, the proportion of 3‐phosphate was almost as high as 100%. In molecularly imprinted polymer synthesized using 5,6,7,8‐Tetrahydro‐2‐naphthol as a template to protect hydroxyl group at C3, the proportion of 17‐phosphate reached 98.2%. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Selective recognition of beta‐cypermethrin by molecularly imprinted polymers based on magnetite yeast composites

Magnetic nanoparticles were attached to yeast by co‐precipitation reaction of FeCl₃·6H₂O and FeCl₂·4H₂O. Then, based on magnetite yeast composites (M@Y), the magnetic molecularly imprinted polymers (MMIPs) were synthesized for the selective recognition of beta‐cypermethrin (PP₃₂₁). MMIPs were characterized by scanning electron microscopy, X‐ray diffraction, vibrating sample magnetometer, Fourier transform infrared analysis, thermogravimetric analysis, and elemental analysis. MMIPs exhibited uniform morphology and magnetic property (Ms = 17.87 emu/g) and thermal stability. Batch mode adsorption studies were carried out to investigate the specific adsorption equilibrium, kinetics, and selective recognition. The Langmuir isotherm model was fitted to the equilibrium data slightly better than the Freundlich model, and the adsorption capacity of MMIPs was 39.64 mg/g at 298 K. The kinetic properties of MMIPs were well described by the pseudo‐second‐order equation. Hydrogen bonds between methacrylic acid and PP₃₂₁ were mainly responsible for the adsorption mechanism. The MMIPs prepared were applied to the separation of PP₃₂₁ from experimental samples successfully. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Preparation and evaluation of a molecularly imprinted polymer for tolazoline

A uniformly sized molecularly imprinted polymer for the peripheral vasodilator drug tolazoline (T‐MIP) was prepared, and a nonimprinted polymer (NIP) was also synthesized in the same way but in the absence of the template. The T‐MIP was prepared with methylacrylic acid as functional monomer and ethylene glycol dimethacrylate as crosslinker by a multistep swelling and polymerization method. These imprinted materials were characterized by scanning electron microscopy, nitrogen adsorption, and static adsorption experiments. Binding studies were also performed to evaluate the uptake of T‐MIP and NIP with the results that T‐MIP had a significantly higher binding capacity for tolazoline (T) than did NIP. The maximum static adsorption capacities of T‐MIP and NIP for T were 78.9 and 38.8 μmol/g, respectively. The T‐MIPs and NIPs were used as stationary phases of solid‐phase extraction (SPE), and a relative selectivity coefficient (k′) value of 5.21 was obtained, which showed that the T‐MIP sorbent had higher selectivity than the NIP sorbent. The method was applied to the determination of T in urine samples. The prepared polymer sorbent showed promise for SPE for gas chromatography determination of T in urine samples. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation of water‐compatible antifungal polyurethane with grafted benzimidazole as the antifungal agent

We compared two series of benzimidazole (BI)‐grafted polyurethane (PU), one of which was water‐compatible, to compare their antifungal activities. The water‐compatible PU series had an additional 2,2‐bis(hydroxymethyl)propanoic acid group in the PU backbone. The water‐compatible PU series had a lower crosslinking density and tensile strength compared to the other PU series with increasing BI content. Although ordinary PU did not suppress fungal growth (Chaetomium globosum), the water‐compatible PU completely suppressed the growth even though it contained half as many BI groups. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41676.     

Molecularly imprinted polymers for the selective recognition of l‐phenylalanine based on 1‐buty‐3‐methylimidazolium ionic liquid

To enhance the affinity of 4‐vinyl pyridine to l ‐phenylalanine (l ‐Phe) and convert the imprinting process from the aqueous phase to the organic phase, an oil‐soluble amino acid ionic liquid was introduced as a template. In this study, 1‐butyl‐3‐methylimidazolium α‐aminohydrocinnamic acid salt was first applied to prepared surface molecularly imprinted polymers (MIPs) in acetonitrile for the selective recognition of l ‐Phe. Fluorescence quenching analysis of the functional monomer on the template was investigated under different conditions to study the imprinting mechanism. Several binding studies, such as the sorption kinetics, sorption thermodynamics, and solid‐phase extraction application, and the chiral resolution of racemic phenylalanine were investigated. The binding isotherms were fitted by nonlinear regression to the Freundlich model to investigate the recognition mechanism. The affinity distribution analysis revealed that polymers imprinted by ionic liquid showed higher homogeneous binding sites than those imprinted by l ‐Phe. The competition tests were conducted by a molecularly imprinting solid‐phase extraction procedure to estimate the selective separation properties of the MIPs for l ‐Phe. The target MIP was shown to be successfully for the separation of l ‐Phe from an amino acid mixture. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42485.     

Direct nanolayer preparation of molecularly imprinted polymers immobilized on multiwalled carbon nanotubes as a surface-recognition sites and their characterization

Molecular imprinting is a method for making artificial receptor sites in a polymer. This article reports the direct nanolayer immobilization of molecularly imprinted polymers (MIPs) on hydroxyl-functionalized multiwalled carbon nanotubes (MWCNTs) without any binder to improve their characteristics. MIPs were formed for hydrochlorothiazide (HCT) as a template on the surface of the MWCNTs with methacrylic acid (functional monomer) and ethylene glycol dimethacrylate (crosslinking agent) with a thermal polymerization technique. The morphology and stability of the immobilized molecularly imprinted polymers on the surface of multiwalled carbon nanotubes (MIPCNTs) was characterized with scanning electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The resulting MIPCNTs demonstrated favorable selectivity, good stability, and a higher adsorption capacity for the template molecule (93.0 μg/mg) compared to products created by bulk polymerization. The adsorption kinetics of HCT at the surface of the MIPCNTs was in agreement with the second-order rate equation. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Magnetic molecularly imprinted polymers obtained by photopolymerization for selective recognition of penicillin G

Some of the most important life-saving medications are β-lactam antibiotics (such as Penicillin G). However, these medicines have not adequately been discharged into the environment; penicillin residues offer health risks and enhance the development of resistances. Thus, its selective separation from complex matrices is a challenge worth tackling. A novel strategy of synthesis, by photopolymerization, was applied to develop magnetic molecular imprinted polymers (mag-MIPs) aiming the recognition of penicillin G (also known as benzylpenicillin). Photopolymerization, when compared with the more common thermopolymerization, has the advantage of occurring at lower temperatures, which prevents analyte degradation. The Mag-MIP presented higher surface area than the conventional MIP and good adsorption capacity of the analyte while maintaining its selectivity. The synthesized material was characterized by X-ray diffraction, showing that the magnetite nanoparticles were formed and the MIP polymerization on their surface was performed, once the material was amorphous. Furthermore, the pore formation was evaluated by BET, indicating a high surface area (832 m² g⁻¹) and large pore volume (0.80 cm³ g⁻¹) in the mag-MIP compared to the magnetic non-imprinted polymer (mag-NIP: 147 m² g⁻¹ and 0.33 cm³ g⁻¹). © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48496.