Surface molecularly imprinted polymer prepared by reverse atom transfer radical polymerization for selective adsorption indole

The preparation of indole molecularly imprinted polymers (indole‐MIPs) using 4‐vinylpyridine as functional monomer, silica gel as matrix were used to adsorb indole from fuel oil specifically. The reverse atom transfer radical polymerization (RATRP) technology was introduced to prepare the surface molecularly imprinted polymers, and the precipitation polymerization was adopted in the preparation process. The obtained indole‐MIPs were characterized by nitrogen adsorption, Fourier transform infrared spectrometry and scanning electron microscopy. The results show that indole‐MIPs were provided with the larger surface areas and more pores. The adsorption capacity of indole‐MIPs was 31.80 mg g^?1 at 298 K, and the adsorption equilibrium was reached in a short time. The adsorption process was spontaneous by thermodynamic analysis, and an appropriate decrease in temperature could enhance the adsorption capacity. The adsorption process obeyed pseudo‐second‐order kinetic model by kinetics analysis. The isotherm analysis results show that both Langmuir and Sips equations were suitable to experimental data. The selective adsorption and reusable performance of indole‐MIPs were favorable. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40473.     

Solid-phase extraction materials based on molecularly imprinted polymers for recognition of pyrethroids

A novel recognition material for detection of kinds of pyrethroids was successfully synthesized by molecular imprinting technology. 3-Phenoxybenzoic acid (PBA) usually could be the antigen to prepare the polyclonal antibody. In this work, the recognition material was prepared utilizing PBA as the template, methacrylicacid as the functional monomer and ethylene glycol dimethacrylate as the crosslinker. The recognition material was characterized by atomic force microscope, adsorption equilibrium and selectivity experiments. The results showed that the recognition material has been successfully prepared and recognized four pyrethroids (fenpropathrin, deltamethrin, fenvalerate, and cyhalothrin). The recognition material was utilized as sorbents in solid-phase extraction for separation and detection of pyrethroids in practically samples. Under the optimal conditions, the recoveries were ranging from 74.3 to 111.0%. Therefore, novel materials for pyrethroids are very promising for future applications. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48919.     

Molecularly imprinted polymer beads prepared by pickering emulsion polymerization for steroid recognition

Pickering emulsion polymerization was used to synthesize molecularly imprinted polymer beads for the selective recognition of 17‐β‐estradiol under aqueous conditions. Scanning electron microscopy analysis indicated that the imprinted polymer beads had a small diameter with a narrow size distribution (18.9 ± 2.3 μm). The reduction in particle size achieved in this study was attributed to the altered polarity of the stabilizing nanoparticles used in the Pickering emulsion. The imprinted polymer beads could be used directly in water and showed a high binding affinity for the template molecule, 17‐β‐estradiol, and its structural analogs. These water‐compatible polymer beads could be used as affinity adsorbents for the extraction and analysis of low‐abundance steroid compounds in aqueous samples. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39606.     

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     

Clozapine recognition via molecularly imprinted polymers; bulk polymerization versus precipitation method

Two clozapine (CLZ) imprinted polymers were prepared by bulk and precipitation methods. Methacrylic acid and ethylene glycol dimethacrylate (EDMA) were used as functional and crosslinker monomers, respectively. The mean diameter and particle size distribution of the imprinted (P‐MIP) and nonimprinted (P‐NIP) particles obtained in precipitation method were examined. A conventional batch‐adsorption test was applied for characterization of CLZ–polymer interaction. Dissociation constant (K_D) and maximum binding sites (B_max) were calculated using Scatchard analysis. To evaluate the recognition properties of polymers, phenytoin (PTN) binding to each polymer was also studied and compared to CLZ. The imprinting factor (IF) and selectivity factor (α) were also determined for each polymer. Average diameter and polydispersity of P‐MIP were 925 nm and 0.17, respectively. The data for P‐NIP were 1.05 μm and 0.18. The K_D, IF, and α values calculated for P‐MIP were 0.45 μM, 3.26, and 17.43, respectively. The data for imprinted polymer, prepared by bulk polymerization (B‐MIP), were 14.5 μM, 1.95, and 3.67. These results demonstrated that precipitation polymerization is a more convenient, more effective, and more reproducible method than bulk polymerization for the synthesis of uniformly sized micron and submicron‐imprinted polymer particles. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

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     

Precipitation polymerization of molecularly imprinted polymers for recognition of melamine molecule

Molecular imprinted polymer microspheres (MIPs) were prepared by precipitation polymerization using melamine as template molecule, methacrylic acid (MAA) as functional monomer, trimethylol‐propane trimethacrylate (TRIM) as crosslinking agent, acetonitrile as solvent and dispersion medium. Release of the template was performed by continuous extraction with methanol containing 10% acetic acid. The microspheres were observed by scanning electron microscopy (SEM). The perfect microspheres were produced when the addition of crosslinker was 7.48 mmol. The binding capacity of MIPs was examined, Q_max = 68.36 μmol g^?1, and the dissociation constant at binding site of MIPs, K_d = 0.761, was estimated. Compared with the performance of conventional imprinted polymer, the imprinted microspheres showed high selectivity in special binding to template molecule. The imprinted microspheres could be used as the stationary phase in HPLC or SPE for selective extraction of melamine in daily products. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Uniform star‐polystyrene nanoparticles prepared by emulsion atom transfer radical polymerization

Pentaerythritol (PT) was converted into four‐arm initiator pentaerythritol tetrakis(2‐chloropropionyl) (PT‐Cl) via reaction with 2‐chloropropionyl chloride. Uniform (monodisperse) star‐polystyrene nanoparticles were prepared by emulsion atom transfer radical polymerization of styrene, using PT‐Cl/CuCl/bpy (bpy is 2,2′‐dipyridyl) as the initiating system. The structures of PT‐Cl and polymer were characterized by Fourier transform infrared spectroscopy and nuclear magnetic resonance. The morphology, size and size distribution of the star‐polystyrene nanoparticles were characterized by transmission electron microscopy, atomic force microscopy and photon correlation spectroscopy. It was found that the average diameters of star‐polystyrene nanoparticles were smaller than 100 nm (30–90 nm) and monodisperse; moreover, the particle size could be controlled by the monomer/initiator ratio and the surfactant concentration. The average hydrodynamic diameter (D_h) of the nanoparticles increased gradually on increasing the ratio of styrene to PT‐Cl and decreased on enhancing the surfactant concentration or increasing the catalyst concentration. Copyright © 2011 Society of Chemical Industry     

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.     

Crosslinking diversity on network morphology,template binding,and template transport of molecularly imprinted polymers prepared via living radical polymerization

The objective of this work is to study the effects of altering the chain building blocks and the reaction on template binding and transport parameters of imprinted polymer gels. The characterization of imprinted poly(diethylaminoethylmethacrylate‐co‐hydroxyethylmethacrylate‐co‐polyethyleneglycol(n)dimethacrylate) polymer gels prepared via free (FRP) or living (LRP) radical polymerization with varying crosslinking monomer lengths (number of ethylene glycol repeat units of 1, ～4.5, ～9) and concentrations (1, 5, 10, 50%) is presented. All imprinted networks prepared via LRP exhibited significantly higher template binding affinities and capacities as well as significantly lower template diffusion coefficients compared to those prepared via FRP. Synthesizing imprinted polymers via LRP results in much smaller and relatively constant dispersities of polymer chains compared to imprinted polymers prepared via FRP. Therefore, LRP has a profound structural effect on the imprinted polymer network leading to increased homogeneity in the mesh structure which enhances the molecular imprinting effect. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3588–3599, 2013     

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.     

原子转移自由基乳液聚合研究进展

原子转移自由基聚合(ATRP)作为一种可控/活性聚合方法,可对聚合物结构进行精确控制;乳液聚合以水作为分散介质,具有经济、环保等特点。因此,乳液ATRP结合了两者的优点,具有工业化生产的潜力。首先分析了影响乳液ATRP的各种因素,然后综述了正向ATRP、RATRP(反向ATRP)、SR&NI ATRP(正向/反向同时进行的ATRP)和AGET ATRP(电子转移活化剂ATRP)等机制及研究进展,最后对乳液ATRP的发展方向进行了展望。     

Molecularly imprinted polymer prepared by Pickering emulsion polymerization for removal of acephate residues from contaminated waters

A molecularly imprinted polymer (MIP) prepared with Pickering emulsion polymerization was designed by a computational approach for removal of acephate from aqueous solution. Methacrylic acid, ethylene glycol dimethacrylate, and chloroform were screened as the optimal functional monomer, crosslinker, and porogen by the Gaussian 03 package using the density functional theory method. The polymerization was carried out in an oil‐in‐water emulsion using nano‐SiO₂ particles as stabilizer instead of a toxic surfactant. The characterization results indicated that the prepared MIP had a porous and hollow core, and the particle size was approximately 20 μm. The binding and recognition abilities of MIP for acephate were studied through equilibrium adsorption analysis and selectivity analysis. The results showed that the MIP had high binding capacity and excellent selectivity for acephate. The saturated binding amount could reach 6.59 × 10³ μg/g. The Langmuir isotherm model gave a good fit to the experimental data. Moreover, the results of a reusability analysis and practical application suggested that the prepared MIP provides the potential for removal of acephate residues from aqueous solution. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43126.     

Mixed templates molecularly imprinted solid‐phase extraction for the detection of sulfonamides in fish farming water

Highly selective molecularly imprinted polymers (MIPs) that absorb sulfonamides (SAs) are prepared using two types of SAs as mixed templates, 2‐vinylpyridine as the functional monomer and ethylene glycol dimethacrylate as the crosslinker. The optimum combination of the mixed templates, their adsorption effect and the imprinting mechanism are evaluated based on SPE recoveries of a family of analytes, equilibrium binding, BET surface area analysis and UV. The results indicate that the mixed templates not only optimize the cavities of the MIPs but also improve the MIPs selectivity and adsorption capacity for the target analytes in aqueous solution. Therefore, MIPs are used for the quantitative analysis of SAs in fish farming water using off‐line SPE coupled to HPLC/DAD. The recovery and RSD were 84.16–101.19 and 1.98–7.10%, respectively. Four SAs analytes were detected in four types of water samples in the range of 8.49–74.60 ng L^?1. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41491.     

Molecularly imprinted nanoparticles prepared by core‐shell emulsion polymerization

Submicron core‐shell polymer particles, with molecularly imprinted shells, were prepared by a two‐stage polymerization process. Particles of this type, prepared with a cholesterol‐imprinted ethyleneglycol dimethacrylate shell and in the absence of porogen, were found to be 76 nm in diameter with a surface area of 82 m² g⁻¹. Cholesterol uptake from a 1 mM solution in isohexane was measured at both 10 and 30 mg mL⁻¹, with the imprinted polymer showing considerable binding (up to 57%). Imprinted but not hydrolyzed and hydrolyzed nonimprinted polymers showed very low uptakes (≤4.5%) and a phenol‐imprinted polymer showed reduced binding (36%) under the same conditions. Imprinted shells were also prepared over superparamagnetic polymer cores and over magnetite ferrocolloid alone. The cholesterol binding to magnetic particles was very similar to that of equivalent nonmagnetic materials. Magnetic particles could be sedimented in as little as 30 s in a magnetic field. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1851–1859, 2000     

Direct synthesis of surface molecularly imprinted polymers based on vinyl–SiO2 nanospheres for recognition of bisphenol A

Molecularly imprinted polymers (MIP) with high performance in selectively recognizing bisphenol A (BPA) were prepared by using a novel and facile surface molecular‐imprinting technique. Vinyl‐functionalized, monodispersed silica spheres were synthesized by a one‐step emulsion reaction in aqueous solution. Then, BPA surface molecularly imprinted polymers (SMIP) were prepared by polymerization with 4‐vinylpyridine as the functional monomer and ethylene glycol dimethacrylate as the crosslinker. Maximal sorption capacity (Q_max) of the resulting SMIP was up to 600 μmol g^?1, while that of nonimprinted polymers was only 314.68 μmol g^?1. Kinetic binding study showed that sorption capacity reached 70% of Q_max in 20 min and sorption equilibrium at 80 min. SMIP had excellent accessibility and affinity toward BPA, for the selectivity coefficients of SMIP for BPA in respect to phenol, p‐tert‐butylphenol, and o‐phenylphenol were 3.39, 3.35, and 3.02, respectively. The reusage process verified the SMIP owning admirably stable adsorption capacity toward BPA for eight times. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Fe‐mediated ARGET atom transfer radical polymerization of methyl methacrylate in ionic liquid‐based microemulsion

Poly(methyl methacrylate) (PMMA) was synthesized by activator regenerated by electron transfer (ARGET) atom transfer radical polymerization (ATRP) of MMA in ionic liquid‐based microemulsion with polyoxyethylene sorbitan monooleate (Tween 80) as surfactant. The polymerization was carried out at 25°C with CCl₄ as initiator, FeCl₃·6H₂O/N,N,N′,N′‐tetramethyl‐1,2‐ethanediamine (TMEDA) as catalyst complex in the presence of reducing agent ascorbic acid (VC). The polymerization kinetics showed the feature of controlled/″living″ process as evidenced by a linear first‐order plot. The well‐controlled polymers were obtained with narrow polydispersity indices and the ionic liquid‐based microemulsions were transparent with a particle size less than 30 nm. The obtained polymer was characterized by ¹H NMR and gel permeation chromatography. The chain extension was successfully achieved by the obtained PMMA macroinitiator/FeCl₃·6H₂O/TMEDA/VC initiator system based on ARGET ATRP method. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Molecularly imprinted smart cryogels for selective nickel recognition in aqueous solutions

Smart polymers with fast response to slight changes show high practicability in separation and removal applications, such as water and wastewater treatment. Molecular imprinted polymers (MIPs) are designed to possess specific binding sites enabling the recognition of the target analytes. In this article, the newly synthesized smart adsorbents were used for the selective removal of nickel [Ni(II)] ions from aqueous solutions, which have dual (pH and temperature) memory for the recognition of Ni(II) ions due to the self-assembled recognition sites in MIP structure. The Ni(II)-MIP smart cryogels were prepared by cryopolymerization of N-isopropylacrylamide (NIPAm) and N-methacryloyl-l -histidine (MAH) monomers to incorporate their smart features for removal of Ni(II) ions in a selective and temperature-modulated way. The maximum binding capacity of Ni(II) ions onto MIP smart cryogel was determined at pH 6 as 414 μg g⁻¹ at 20°C and only 104.5 μg g⁻¹ at 40°C, respectively. The adsorption reached an equilibrium within 30 min, while 85% of the bound amount of Ni(II) ions was achieved in only 15 min. This unique MIP cryogel as a smart and selective adsorbent was able to remove Ni(II) ions immediately by a significant temperature and pH change as an alternative application for water and wastewater treatment.     

Surface molecularly imprinted polymer microspheres based on nano‐TiO2 for selective recognition of kaempferol

The molecular imprinting technique is a new method for preparing molecularly imprinted polymers (MIPs) with specific molecular recognition sites for certain target molecules. In this study, a novel, facile preparation method was presented, called “seed precipitation polymerization,” for the synthesis of MIPs via surface imprinting and a support matrix. In the polymerization process, kaempferol was used as the template molecule, methacrylic acid as the functional monomer, nano‐TiO₂ as the support, azodiisobutyronitrile as the initiator, and ethylene glycol dimethacrylate as the crosslinker in acetonitrile solvent. The synthesized T‐MIP and MIP were analyzed by infrared spectroscopy and scanning electron microscopy. In addition, the obtained polymers were evaluated by adsorption isotherms and dynamic curves for their selective recognition properties for kaempferol. The results show that T‐MIP shows regular spherical particles; the adsorption dynamic curves of T‐MIP show that the adsorption capacity increases with time and reaches a maximum value and then finally reaches equilibrium, and the T‐MIP exhibits a higher affinity for kaempferol than does the MIP. The adsorption follows pseudo‐second‐order kinetics, the Freundlich adsorption equation fits the experimental data well, and there is strong evidence for multiple‐layer adsorption. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44888.     

A molecularly imprinted polymer as artificial receptor for the detection of indole‐3‐carbinol

Molecularly imprinting polymer technology is used to prepare a molecularly imprinted polymer (MIP) for the selective recognition of indole‐3‐carbinol (I3C), a chemopreventive and chemotherapeutic phytochemical associated with the anticancer activities of cruciferous vegetables. Prepolymerization study via nuclear magnetic resonance technique is done to choose the best functional monomer that establishes more interaction with the template. The prepared MIP is tested before in batch experiments and subsequently used as solid‐phase extraction sorbent for the selective detection of I3C from standard solutions. In order to verify the selectivity of the MIP, the binding of structurally related compounds, such as indole‐3‐acetonitrile, teophylline, and tryptophan, on the polymer is investigated. The experiments indicate that the MIP is highly selective for I3C with an association constant of K_a = (1.37 ± 0.07) × 10³ M^?1. Standard mixture solution loaded on MIP‐SPE cartridge give a recovery of 95% for I3C, while the other compounds are totally eluted during washing step. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40819.