Solvent‐free synthesis of chiral molecularly imprinted polymers: Porosity control using a nano‐sized solid porogen

Molecularly imprinted polymers (MIPs) have been synthesized in the absence of a solvent using fumed silica nanoparticles to create a porous network. The method employed led to a chiral imprinting effect and allowed for an excellent control over the internal morphology of imprinted and non‐imprinted polymer (NIP) materials. The polymers possess high surface areas (>300 m²) and identical pore size (112 Å). The MIP exhibited an imprinting factor (IF) of 9 and a selectivity value (α) of 1.83 for (?)‐ephedrine. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44104.     

Preparation and evaluation of magnetic imprinted polymers for 2,4,6‐trinitrotoluene by surface imprinting

A safe and facile approach for the preparation of magnetic molecularly imprinted polymer nanospheres for 2,4,6‐trinitrotoluene (TNT) recognition is reported. The imprinted nanospheres were synthesized using TNT as the imprinting molecule, acrylamide as the functional monomer, N,N'‐methylenebisacrylamide as the crosslinker and magnetic particles as the support. The structure of the materials was identified via Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy and transmission electron microscopy. Static adsorbing experiments were carried out and Scatchard plot analysis showed that two kinds of receptor sites were formed in the imprinted materials. The adsorption equilibrium constant and the maximum adsorption capacity were evaluated. These results indicated that the imprinted nanospheres have higher adsorption capacity and selectivity for TNT than non‐imprinted polymer nanospheres with the same composition. © 2013 Society of Chemical Industry     

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     

Synthesis of lysozyme imprinted column with macroporous structure and enhanced selectivity: Utilization of cryogelation technique and electrostatic functional monomers

Applicability of molecularly imprinted polymers (MIP) in conventional protein separation processes demands monolithic construction of columns with macroporous structure in addition to the high specificity and adsorption capacity. In this study, therefore, lysozyme (Lyz) imprinted monolithic cryogel columns were synthesized using electrostatic functional monomers (EFMs) to provide strong interactions between template and polymer, leading to specific recognition and capture of Lyz. SEM images and FTIR spectroscopy analysis confirmed the macroporous structure and presence of EFMs in the samples. Adsorption isotherms, heterogeneity, and breakthrough curves as well as selectivity of the molecularly imprinted cryogels (EFMs‐MIC) and non‐imprinted cryogels (EFMs‐NIC) were investigated. Results showed effective imprinting with a maximum adsorption capacity of 211 mg/g and a high imprinting factor (IF) of 4.2 at low Lyz concentrations. A high relative selectivity coefficient of 7.24 was obtained for Lyz over cytochrome c, a competing protein, indicating that the imprinted sites could well distinguish Lyz. Reusability of MICs was also examined, where insignificant changes were observed in the cryogel adsorption/desorption characteristics after four cycles. Therefore, it is suggested to use EFMs and cryogelation in the synthesis of imprinted monolithic cryogels column for application in conventional protein separation processes. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42880.     

Nickel(II)‐imprinted monolithic columns for selective nickel recognition

Ni²⁺‐imprinted monolithic column was prepared for the removal of nickel ions from aqueous solutions. N‐Methacryloyl‐L ‐histidine was used as a complexing monomer for Ni²⁺ ions in the preparation of the Ni²⁺‐imprinted monolithic column. The Ni²⁺‐imprinted poly(hydroxyethyl methacrylate‐N‐methacryloyl‐L ‐histidine) (PHEMAH) monolithic column was synthesized by bulk polymerization. The template ion (Ni²⁺) was removed with a 4‐(2‐pyridylazo) resorcinol (PAR):NH₃? NH₄Cl solution. The water‐uptake ratio of the PHEMAH–Ni²⁺ monolith increased compared with PHEMAH because of the formation of nickel‐ion cavities in the polymer structure. The adsorption of Ni²⁺ ions on both the PHEMAH–Ni²⁺ and PHEMAH monoliths were studied. The maximum adsorption capacity was 0.211 mg/g for the PHEMAH–Ni²⁺ monolith. Fe³⁺, Cu²⁺, and Zn²⁺ ions were used as competitive species in the selectivity experiments. The PHEMAH–Ni²⁺ monolithic column was 268.8, 25.5, and 10.4 times more selective than the PHEMAH monolithic column for the Zn²⁺, Cu²⁺, and Fe³⁺ ions, respectively. The PHEMAH–Ni²⁺ monolithic column could be used repeatedly without a decrease in the Ni²⁺ adsorption capacity. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

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.     

Dye‐molecular‐imprinted polysiloxanes. II. Preparation,characterization, and recognition behavior

Microsphere silica (AMS) was prepared by the sol–gel method and used for the synthesis of dye‐molecular‐imprinted polysiloxanes. These were prepared by the cohydrolysis and polycondensation of the AMS with functional organosilicone monomers (N‐phenylaminomethyl triethoxysilane, 3‐aminopropyl triethoxysilane, and 4‐aza‐6‐aminohexyl triethoxysilane) in the presence of a template molecule of disperse red (or disperse blue or water‐soluble dye) followed by the removal of the template molecule. The molecular‐imprinting and nonimprinting polysiloxanes were characterized by elemental analysis, diffuse‐reflectance Fourier transform infrared spectroscopy, and scanning electron microscopy. Their adsorption behavior toward the template molecule and nontemplate molecule was investigated. The molecular‐imprinting polysiloxane exhibited higher selective recognition properties toward the template molecule than the nonimprinting polysiloxane. In the experimental conditions, their adsorption isotherms were a good fit with the Langmuir model. The distribution coefficient value of water‐soluble‐dye‐imprinted polysiloxane was the highest among the three imprinting polysiloxanes under the experimental conditions. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 637–643, 2004     

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.     

Preparation and application of tectoridin‐imprinted magnetite nanoparticles

In this work, the tectoridin‐imprinted magnetite nanoparticles (TIMNPs) were firstly prepared by using tectoridin as template molecule, methacrylic acid as functional monomer, styrene as crosslinking agent, and superparamagnetic Fe₃O₄ particles as magnetic component. TIMNPs with a size of about 161 nm were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier transform infrared (FT‐IR), X‐ray diffraction (XRD), vibrating sample magnetometer (VSM), and thermogravimetric analysis (TGA). Rebinding experiments were carried out to determine the specific binding properties and adsorption selectivity. The maximum number of binding sites was 69.58 μmol/g and there was only one kind of binding sites existed in TIMNPs. The relative separation factors for tectoridin with its analogues such as baicalin and atenolol were 2.63 and 2.66, respectively. The results indicated that the synthesized TIMNPs had excellent saturation magnetization, binding capacity, and absorption selectivity. TIMNPs could be one of the most promising candidates for tectoridin extraction. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43806.     

Hypercrosslinked silole‐containing microporous organic polymers with N‐functionalized pore surfaces for gas storage and separation

Novel hypercrosslinked microporous organic polymers (MOPs) derived from N‐functionalized siloles as basic building units have been designed and synthesized via Friedel–Crafts alkylation reaction. The resulting N‐functional silole‐containing polymer networks exhibit high thermal stabilities and moderate Brunauer–Emmett–Teller surface area ranging from 666 to 1137 m² g^?1. The incorporation of carbazole or triphenylamine moieties into the polymer skeleton increases the number of electron donating basic nitrogen sites in the porous frameworks. Thus, the corresponding polymer PDMCzS shows enhanced CO₂ adsorption capacities of 3.23 mmol g^?1 at 273 K and 1.13 bar, and higher CO₂/N₂ selectivity (43.99) at 273 K than the analogous silole‐containing polymers P1–P3. These results demonstrated that the N‐functionalized silole‐containing polymer network is a very promising candidate for potential applications in post‐combustion CO₂ capture and sequestration. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45907.     

Rational design and preparation of dibenzothiophene‐targeting molecularly imprinted polymers with molecular dynamics approaches and surface‐initiated activators regenerated by electron‐transfer atom‐transfer radical polymerization

Nine molecular dynamic simulations of molecular‐imprinting prepolymerization systems were performed to investigate the effects of the type and concentration of crosslinkers (CLs) on key template (T)–functional monomer (FM) complexes. Subsequent analyses revealed that the system with divinylbenzene as the CL had the most stable T–FM complexes, and the mass percentage concentration of divinylbenzene in the prepolymerization system was 9.4%. Nine corresponding imprinted polymers were synthesized by the coupling of the surface‐initiated activator regenerated by electron‐transfer atom‐transfer radical polymerization technique with the hierarchical‐imprinting technique to validate the reliability of the simulation results. The structural properties of the optimal adsorbent were characterized by IR spectrophotometry, scanning electron microscopy, and nitrogen sorption measurements. The Langmuir isotherm fitted the equilibrium data best, and the kinetic data (within 30 min) were well described by the pseudo‐second‐order model. Meanwhile, the prepared adsorbent displayed a higher selectivity to dibenzothiophene compared with other analogs. Finally, the adsorbent was successfully applied for the deep desulfurization of the gasoline sample. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42629.     

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     

Graphene‐based molecularly imprinted polymer for separation and pre‐concentration of trace polycyclic aromatic hydrocarbons in environmental water samples

A composite of reduced graphene oxide and pyrene‐imprinted polymer was synthesized and employed as a solid phase for extraction of five selected polycyclic aromatic hydrocarbons (PAHs) from water samples. Gas chromatography‐time of flight/mass spectrometry was employed in the analysis of the extracts. The composite was prepared by a free radical polymerization of methacrylic acid and 4‐vinylpyridine as monomers and ethylene glycol dimethacrylate as a crosslinker. The adsorption studies were carried out through batch binding studies. The binding capacity for the imprinted and non‐imprinted composite was 101.83 and 68.21 µg g^?1, respectively. The adsorption followed the pseudo 2nd order and well fitted the Langmuir isotherm. Mean recoveries ranging from 73% to 105.4% for both spiked deionized water and environmental water samples were obtained when the imprinted composites were employed in solid phase extraction of the PAHs. The composites could be re‐used for five times without a significant loss in recoveries. The proposed method was employed for the analysis of spiked environmental water samples and did not show significant changes in the recoveries showing there were no matrix interferences. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45300.     

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     

Comparative analysis of atrazine molecularly imprinted polymers using acetonitrile and toluene as solvents

Acetonitrile and toluene are solvents commonly used for the synthesis of atrazine molecularly imprinted polymers (MIPs), but their effects have seldom been compared in the same imprinting system. In this paper, effects of the two solvents in an atrazine molecular imprinting system were evaluated theoretically and experimentally. A polarizable continuum model was adopted, and it was found that using the two solvents, the energy difference for the atrazine–methacrylic acid complex between vacuum and solution was not the same. The two types of MIPs prepared using different solvents vary in morphology, porosity, binding capacity, and specificity. All of these results suggest that the abilities of the solvents used to form hydrogen bonds with other compounds in the system are different. The porogen imprinting effect of the solvents also has an influence on binding capacity. Compared to MIPs synthesized using acetonitrile as solvent (MIPs-ACN), MIPs synthesized using toluene as solvent (MIPs-PhMe) have fewer but larger pores and exhibit much higher adsorption capability but less rigorous specificity. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47190.     

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.     

Bio‐inspired synthesis of molecularly imprinted nanocomposite membrane for selective recognition and separation of artemisinin

Inspired from the highly bioadhesive performance of mussel protein, a simple, yet efficient synthetic method for efficiently imprinting of Artemisinin (Ars) was developed to prepare the bio‐inspired molecularly imprinted membranes (MIMs) via atom transfer radical polymerization (ATRP). In this work, attributed to the unique properties of polydopamine (pDA) modified layers and ATRP technology, the uniform recognition sites for efficiently selective extraction of the Ars with high stability could be obtained on the MIMs surfaces. In addition, the maximum adsorption capacity of the MIMs is 158.85 mg g^?1 by the Langmuir isotherm model, which is remarkable higher than NIMs. Additionally, because of the formation of the uniform specific recognition cavities on membrane surfaces, the as‐prepared MIMs exhibited a rapid adsorption dynamics and well‐fitted for the pseudo‐second‐order rate equation, also, possessed an excellent per‐selectivity performance (β_{artemether/Ars} values is 0.18) of template molecule, which clearly demonstrated the potential value of this method in the selective separation and purification of Ars. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43405.     

Evaluation of aminoquinoline‐imprinted polymers and the recognition mechanism

Three molecularly imprinted polymers P(2‐AQ), P(3‐AQ), and P(8‐AQ) based on methacrylic acid (MAA)–ethylene glycol dimethacrylate were prepared using isomers 2‐aminoquinoline (2‐AQ), 3‐aminoquinoline (3‐AQ), and 8‐aminoquinoline (8‐AQ) as template, respectively, by non‐covalent bulk polymerization technique. Neither P(3‐AQ) nor P(8‐AQ) exhibited imprinting effect for 3‐AQ or 8‐AQ, whereas P(2‐AQ) showed significant imprinting effect for 2‐AQ. This indicates that the position of amino group on the quinoline ring has crucial influence on imprinting effect. The recognition mechanism of P(2‐AQ) was investigated extensively by such methods as selective experiments, comparative study with 2‐aminopyridine‐imprinted polymer, and effect of different kinds of mobile phases. It is confirmed that there are complementary cavities in P(2‐AQ) both in size and in the arrangement of functional groups to 2‐AQ, and MAA binds 2‐AQ via cyclic hydrogen bond. Furthermore, the influence of synthetic conditions on 2‐AQ‐imprinted polymers was explored. We found 2‐AQ‐imprinted polymer synthesized in acetonitrile porogen showed higher imprinting effect for 2‐AQ than that prepared in chloroform. It is deduced that the morphology of the former might be more favorable to 2‐AQ binding, which is also supported indirectly by the fluorimetric experiments estimating the interaction of 2‐AQ with MAA in these two porogens. Additionally, 2‐AQ‐imprinted polymers prepared using two different amounts of acetonitrile exhibited very different imprinting effects, which suggested that porogen amount used in the imprinting process exerted significant influence. In addition to the in‐depth elucidation of the recognition mechanism of 2‐AQ‐imprinted polymer, this article provides the basis for the separation and enrichment of bioactive 2‐AQ. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

硫丹分子印迹聚合物的合成及吸附特性分析

采用分子印迹技术,以α-甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂,偶氮二异丁腈为引发剂,乙腈为致孔剂,合成以硫丹为模板的印迹聚合物微球。首先利用紫外光谱方法研究了模板与功能单体相互作用情况,采用平衡吸附试验对印迹聚合物吸附效率进行了表征,与化学组成相同的空白聚合物相比,印迹聚合物微球对模板分子具有更高的吸附效率,按最佳合成条件得到的印迹聚合物最大表观吸附量达42.56 mmol/g。     

Adsorption of lactic acid onto three ionic liquid‐modified porous polymers

Three ionic liquid (IL)‐modified porous polymers were synthesized and used for the adsorption of lactic acid. The experimental adsorption kinetics and equilibrium data from the IL‐modified polymers were obtained. The kinetic study revealed a low temperature to be advantageous to the adsorption process. The dependence of the level of lactic acid adsorption on the amount of polymer, initial lactic acid concentration, and pH was examined at equilibrium. The maximum efficiency was obtained using the maximum adsorbent dose. A comparison of lactic acid adsorption at different pH revealed anion exchange to be the main interaction between the lactic acid and polymers, not molecular adsorption. The amounts adsorbed were fitted to the Langmuir, Freundlich, and Temkin equations. The equilibrium data for modified polymers (imidazole modified polymer, methylimidazole modified polymer, and ethylimidazole modified polymer) were best represented by the Langmuir and Freundlich isotherm with R² values of 0.99. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013