Crosslinkable functional moiety for the formation of highly crosslinked stable microspheres in the precipitation polymerization

The highly crosslinked stable spherical microspheres were successfully synthesized using styrene and three crosslinking agents having different number of crosslinkable functional moiety in comonomer using the precipitation polymerization. The crosslinking agents are ethylene glycol dimethacrylate (EGDMA), trimethylolpropane trimethacrylate (TMPTMA) and pentaerythritol tetraacrylate (PETRA). The maximum and minimum concentrations for forming the stable spherical particles were ranging at 20-90 mol% for EGDMA, 15-80 mol% for TMPTMA, and 5-40 mol% for PETRA, respectively. The number-average diameter of stable poly(S-co-EGDMA), poly(S-co-TMPTMA), and poly(S-co-PETRA) particles varied 4.1-3.06, 3.94-3.03 and 2.77-1.66 μm, respectively. Since the prepared microspheres are highly crosslinked, no glass transition temperature was observed. The TGA onset point of the thermal degradation temperature increased with the concentration of crosslinking agent and the number of crosslinkable functional moiety, which is EGDMA < TMPTMA < PETRA. As a result, the minimum and maximum concentrations for the formation of stable spherical particles of poly(S-co-EGDMA), poly(S-co-TMPTMA), and poly(S-co-PETRA), the particle size and its distribution, CV, yield and the TGA onset point are significantly affected by the number of the crosslinkable functional moiety. Thus, the number of the crosslinkable functional moiety and the different reactivity as well as the different copolymerization parameters of styrene with (meth)acrylates would influence the composition as well as the rate of formation of stable microspheres.     

Mechanical stability of trimethylolpropane trimethacrylate-based polymers

Trimethylolpropane trimethacrylate (TRIM) was homopolymerized and copolymerized with methyl methacrylate (MMA), glycidyl methacrylate (GMA), and acrylamide (AA), respectively, in various solvents and at various temperatures. For comparison, poly(styrene-co-divinyl benzene) [poly(S-co-DVB)] gels were selected. The mechanical stability was measured by compression of the swollen gels. The porogen served as swelling agent. The compression moduli increased with increasing TRIM concentration in the polymerization. The compression moduli of poly(TRIM) could be increased by copolymerization with low concentrations of comonomer. Low polymerization temperature decreased the mechanical strength of poly(TRIM). A good solvent increased the compression modulus. TRIM-based gels were at least as mechanically stable as were poly(S-co-DVB) gels.     

Preparation and oil-absorptivity of crosslinked polymers containing stearylmethacrylate, 4-t-butylstyrene, and divinylbenzene

Summary The crosslinked polymers, poly(stearylmethacrylate-co-divinylbenzene) [CP(SMA-co-DVB)] and poly(t-butylstyrene-co-divinylbenzene) [CP(tBS-co-DVB)], and CP(SMA-co-DVB)/PtBS IPNs, were prepared by the polymerization of corresponding monomer pairs in the presence of BPO. The structures and thermal properties of CP(SMA-co-DVB), CP(tBS-co-DVB), and the IPN were determined by FT-IR, DSC, and TGA. The oil-absorptivities of CP(SMA-co-DVB) and CP(SMA-co-DVB)/PtBS IPN decreased with increasing concentrations of DVB and tBS, respectively. The highest oil-absorptivities of CP(SMA-co-DVB) and the IPN(PtBS: 25%) were 615 % and 330 %, respectively. The toluene absorptivity of the synthesized polymers decreased in following order: CP(tBS-co-DVB) > CP(SMA-co-DVB) > IPN(PtBS: 25 %) > IPN(PtBS: 50 %) > IPN(PtBS: 75 %) at immersion above 60 min. Received: 4 November 1999/Revised version: 13 December 1999/Accepted: 15 December 1999     

Synthesis of monodisperse crosslinked poly(styrene‐co‐divinylbenzene) microspheres by precipitation polymerization in acetic acid

Poly(styrene‐co‐divinylbenzene) microspheres with size ranging from 1.6 to 1.8 μm were prepared in acetic acid by precipitation polymerization. The particle size and particle size distribution were determined by laser diffraction particle size analyzer, and the morphology of the particles was observed with scanning electron microscope. Besides, effects of various polymerization parameters such as initiator and total monomer concentration, divinylbenzene (DVB) content, polymerization time and polymerization temperature on the morphology and particle size were investigated in this article. In addition, the yield of microspheres increased with the increasing total monomer concentration, initiator loading, DVB concentration and polymerization time. In addition, the optimum polymerization conditions for synthesis of monodisperse crosslinked poly(styrene‐co‐divinylbenzene) microspheres by precipitation polymerization in acetic acid were obtained. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Carbonization of PAN grafted uniform crosslinked polystyrene microspheres

Micrometer-sized polystyrene/poly(styrene-divinylbenzene) and polystyrene/polydivinylbenzene composite particles of narrow size distribution were formed by a single-step swelling process of uniform polystyrene template particles with emulsion droplets of dibutyl phthalate containing benzoyl peroxide and divinylbenzene in the presence or absence of styrene, followed by polymerization of the monomer(s) within the swollen template particles at 70 °C. Porous poly(styrene-divinylbenzene) and polydivinylbenzene uniform microspheres were formed by dissolution of the polystyrene part of the former composite particles. Hydroperoxide conjugated microspheres were formed by ozonolysis of the former porous microspheres. Uniform poly(styrene-divinylbenzene)/PAN and polydivinylbenzene/PAN core/shell microspheres were prepared by room temperature redox graft polymerization of AN onto the hydroperoxide conjugated particles. Uniform carbon microspheres were prepared by carbonization of the core/shell particles at 800 and 1100 °C under dynamic N₂ atmosphere. On the other hand, a similar treatment of the core particles only resulted in destruction of the particle shape. Carbon microspheres of increasing surface area (up to ca. 1000 m²/g) were prepared by activation of the former carbon microspheres with CO₂ at 850 °C. The influence of the carbonization temperature of the core/shell particles and the activation time of the carbon particles on the carbon yield and surface area has been elucidated.     

Rapid pH/temperature-responsive cationic hydrogels with dual stimuli-sensitive grafted side chains

Dual temperature- and pH-sensitive comb-type grafted cationic hydrogels are successfully synthesized by grafting polymeric chains with freely mobile ends, which are composed of both N-isopropylacrylamide (NIPAM) segments and N,N-dimethylamino ethyl methacrylate (DMAEMA) segments, onto the backbone of crosslinked poly(NIPAM-co-DMAEMA) networks. Equilibrium and dynamic swelling/deswelling properties of the prepared hydrogels responding to pH and/or temperature are investigated. The prepared hydrogels demonstrate a lower critical solution temperature (LCST) at about 34 °C and a pK_a value at about pH 7.3. At lower pH and lower temperature, both the swelling degree and the swelling rate of the comb-type grafted hydrogel are larger than those of the normal-type crosslinked hydrogel. The comb-type grafted poly(NIPAM-co-DMAEMA) hydrogel exhibits a more rapid deswelling rate than that of the normal-type hydrogel in response to a pH jump from 2.0 to 11.0 at a fixed temperature. The volume changes of the poly(NIPAM-co-DMAEMA) hydrogels are acute in a series of fixed buffer solutions with an abrupt increase of environmental temperature from 18 °C to a temperature higher than the LCST. The comb-type grafted poly(NIPAM-co-DMAEMA) hydrogels show quite fast shrinking behaviors in response to simultaneous dual temperature and pH stimuli. Drug-release in vitro from the prepared poly(NIPAM-co-DMAEMA) hydrogels is carried out when the environmental temperature and pH are changed synchronously. The results show that the model drug Vitamin B₁₂ is released much more rapidly from the comb-type grafted hydrogel than that from the normal-type hydrogel. The proposed dual temperature/pH-sensitive comb-type grafted cationic poly(NIPAM-co-DMAEMA) hydrogel in this study may find various potential applications, e.g., for fabricating rapid-response smart sensors, actuators, and chemical/drug carriers and so on.     

Effect of nitrobenzene on initiator-fragment incorporation radical polymerization of divinylbenzene with dimethyl 2,2′-azobisisobutyrate

The polymerization of divinylbenzene (DVB) with dimethyl 2,2′-azobisisobutyrate (MAIB) was conducted at 70 and 80 °C in benzene in the presence of nitrobenzene (NB) as a retarder. When the concentrations of DVB, MAIB, and NB were 0.45, 0.50, and 0.50 mol/l, respectively, the polymerization proceeded without any gelation to yield soluble polymers. The polymer yield (up to 65%) and the molecular weight (M_n=1.5-4.2×l0⁴ at 70 °C and 1.3-3.9×l0⁴ at 80 °C) increased with time. The polymer formed in the polymerization at 80 °C for 4 h consisted of the DVB units with (4 mol%) and without double bond (41 mol%), methoxycarbonylpropyl group as MAIB-fragment (48 mol%), and NB unit (7 mol%). Incorporation of such a large number of the initiator-fragments as terminal groups in a polymer molecule indicates that the polymer is of a hyperbranched structure. The polymer showed an upper critical solution temperature (40 °C on cooling) in an acetone-water [14:1 (v/v)] mixture. The results of MALLS and viscometric measurements and TEM observation supported that the polymers formed in the present polymerization have a hyperbranched structure. The polymerization system at 70 °C involved an ESR-observable nitroxide radical formed by the addition of polymer radical to the nitro group of NB. The polymerization was kinetically investigated in dioxane. The initial polymerization rate (R_p) at 70 °C was expressed by R_p=k[MAIB]^0.5[DVB]^0.9[NB]^−0.4. The kinetic results were explained on the basis of the reversible addition of polymer radical to NB and the termination between the polymer radical and the nitroxide radical. The overall activation energy of the polymerization was 27.8 kcal/mol.     

Preparation of polymer/silica/polymer tri-layer hybrid materials and the corresponding hollow polymer microspheres with movable cores

Tri-layer poly(methacrylic acid-co-ethyleneglycol dimethacrylate)/silica/poly(ethyleneglycol dimethacrylate) (P(MAA-co-EGDMA)/SiO₂/PEGDMA) and P(MAA-co-EGDMA)/SiO₂/polydivinylbenzene hybrid microspheres were prepared by distillation precipitation polymerization of ethyleneglycol dimethacrylate (EGDMA) and divinylbenzene (DVB) in the presence of 3-(methacryloxy)propyl trimethoxysilane (MPS)-modified P(MAA-co-EGDMA)/SiO₂ microspheres as the seeds. The polymerization of EGDMA and DVB was performed in neat acetonitrile with 2,2′-azobisisobutyronitrile (AIBN) as initiator to coat the MPS-modified P(MAA-co-EGDMA)/SiO₂ seeds through the capture of EGDMA and DVB oligomer radicals with the aid of vinyl groups on the surface of modified seeds in the absence of any stabilizer or surfactant. Monodisperse P(MAA-co-EGDMA)/SiO₂ core-shell microspheres were synthesized by coating of a layer of silica onto P(MAA-co-EGDMA) microspheres via a sol-gel process, which were further grafted by MPS incorporating the reactive vinyl groups onto the surface to be used as the seeds for the construction of hybrid microspheres with tri-layer structure. Hollow poly(ethyleneglycol dimethacrylate) (PEGDMA) and poly(divinylbenzene) (PDVB) microspheres with movable P(MAA-co-EGDMA) core were subsequently developed after the selective etching of the silica mid-layer from the tri-layer hybrid microspheres in hydrofluoric acid. The morphology and structure of the tri-layer polymer hybrids and the corresponding hollow polymer microspheres with movable P(MAA-co-EGDMA) core were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectra and X-ray photoelectron spectroscopy (XPS).     

Synthesis and Structural Characterizations of “Core–Shell”-Type Nickel-Coated Polymeric Particles

A polystyrene seed with a narrow size distribution was synthesized by the dispersion polymerization method first, then uniformly “swollen up” and cross-linked with divinylbenzene (DVB) utilizing the dynamic swelling polymerization technique. The surface of hollow poly(styrene-co-DVB) particles was coated with nickel by the electroless plating method. The density of the synthesized “core–shell”-type conductive particle was 3.06 g/cm³, significantly lower than the density of pure metallurgical nickel of 8.91 g/cm³. Hence, the sedimentation problem, which often occurs in the blend of high-density metal fillers with a relatively low density polymer matrix, could be overcome as the metal fillers were replaced by the synthesized core–shell-type conductive particles.     

Influence of the swelling history on the swelling kinetics of stimuli-responsive poly[(N-isopropylacrylamide)-co-(methacrylic acid)] hydrogels

The influence of the swelling history on the swelling behavior of poly[(N-isopropylacrylamide)-co-(methacrylic acid)] P[(N-iPAAm)-co-(MAA)] random copolymers hydrogels synthesized by free radical polymerization in solution of N-iPAAm and MAA comonomers crosslinked with tetraethylene glycol dimethyl acrylate (TEGDMA) has been studied. The swelling behavior under pH 7 at 18, 29, 39 and 49 °C of this series of copolymers, previously soaked either at pH 2 or 7 has been investigated. The swelling kinetics of these two series of samples displays different behavior as function of the composition and temperature. However, the equilibrium swelling values only show slight dependences on the previous soaking pH and temperature. When samples are soaked at pH 7, then the swelling at pH 7 follows a first order kinetics, irrespective of the copolymer composition or the temperature at which the experiment has been carried out. In this case, the swelling process is very fast and depends only slightly on temperature. The first order rate constant increases with the MAA content in the hydrogel. Furthermore, the swelling rate of copolymer hydrogels soaked at pH 2, show strong dependence on composition and temperature. They follow an autocatalytic swelling kinetics due to the disruption of hydrogen bond arrangements. An initial slow water uptake is followed by an acceleration process, in which water molecules inside the gel help the next water molecules to come in. Two rate constants, a first-order rate constant and an autocatalytic one have been obtained from the kinetics analysis. They have revealed different temperature dependence which may be due to a balance between hydrophobic and hydrogen bond interactions. The temperature dependence of the swelling kinetics is stronger and more complex for copolymers treated under pH 2 than for copolymers soaked under pH 7.     

Monodisperse hydrophilic polymer microspheres having carboxylic acid groups prepared by distillation precipitation polymerization

Monodisperse hydrophilic polymer microspheres having carboxyl acid group with spherical shape in the range of 160 nm and 1.52 μm were prepared by distillation copolymerizations of (meth)acrylic acid with either ethyleneglycol dimethacrylate (EGDMA) or divinylbenzene (DVB) as crosslinker. Polymerization was carried out with 2,2′-azobisisobutyronitrile (AIBN) as initiator in neat acetonitrile without stirring. The polymer microspheres were formed and precipitated out from the reaction medium during the distillation of the solvent from the reaction system through an entropic precipitation polymerization manner. The effects of the crosslinker degree on the morphology and the loading capacity of the carboxylic acid group of the resultant polymer microspheres were investigated. The growth procedures of poly(DVB-co-AA) microspheres were traced by SEM characterization. The steric stabilization through the pendent chains and surface gel and the electrostatic repulsion from the carboxyl acid groups contribute to the formation of monodisperse polymer microspheres.     

Monodispersed thermoresponsive hydrogel microspheres with a volume phase transition driven by hydrogen bonding

We report the synthesis and characterization of monodispersed thermoresponsive hydrogel microspheres with a volume phase transition driven by hydrogen bonding. The prepared microspheres, composed of poly(acrylamide-co-styrene) (poly(AAM-co-St)) cores and poly(acrylamide)/poly(acrylic acid) (PAAM/PAAC) based interpenetrating polymer network (IPN) shells, were featured with high monodispersity and positively thermoresponsive volume phase transition characteristics with tunable swelling kinetics, i.e. the particle swelling was induced by an increase rather than a decrease in temperature. The monodisperse poly(AAM-co-St) seeds were prepared by emulsifier-free emulsion polymerization, the PAAM or poly(acrylamide-co-butyl methacrylate) (poly(AAM-co-BMA)) shells were fabricated on the seeds by free radical polymerization, and the core-shell microspheres with PAAM/PAAC based IPN shells were finished by a method of sequential IPN synthesis. The microsphere size increased with increasing both AAM and BMA dosages. The increase of hydrophilic monomer AAM dosage resulted in a better monodispersity, but the increase of hydrophobic monomer BMA dosage led to a worse monodispersity. With increasing the crosslinker methylenebisacrylamide (MBA) dosage, the mean diameter of the microspheres decreased and the monodispersity became better. An equimolar composition of AAC and AAM in the IPN shells of the microspheres resulted in a more complete shrinkage for the microspheres at temperatures lower than the upper critical solution temperature. Both BMA and MBA additions depressed the swelling ratio of the hydrodynamic diameter of the microspheres.     

Preparation and structure characterization of hairy nanoparticles consisting of hydrophobic core and thermosensitive hairs

Structural characterization of hairy nanoparticles consisting of poly(styrene-co-glycidyl methacrylate) (St/GMA) core and poly(NIPA-co-vinylimidazole) (NIPA/VIm) hair has been carried out by dynamic light scattering. The hairy molecules were introduced by surface graft-polymerization of a mixture of NIPA and VIm monomers to the St/GMA core particles with the hydrodynamic radius R_H of 135±10 nm. The R_H of St/GMA-core-NIPA/VIm-hair particles was R_H=360±20 nm at 20 °C, which gradually decreased to 285±10 nm by heating to 33.0 °C, and then underwent a sharp decrease to 175±10 nm by further heating to 33.8 °C. The final value went to 159±10 nm at 36 °C. This decrease in R_H is due to the shrinking transition of NIPA/VIm chain by hydrophobic association. The degree of shrinking of the hairy particles is compared with that of bulk NIPA gels from the viewpoint of geometrical constraints.     

Synthesis and characterization of temperature-responsive copolymer of PELGA modified poly(N-isopropylacrylamide)

Novel amphiphilic PELGA modified temperature-responsive copolymer, [(poly(methoxyethylene glycol)-co-poly(lactic acid)-co-poly-(glycolic acid))acrylate-co-poly(N-isopropylacrylamide)-co-poly(N-hydroxymethylacrylamide)] (PELGAA-co-PNIPAAm-co-PNHMAAm) was synthesized by incorporating PELGA as the amphiphilic moiety into poly(N-isopropylamide) with various LA/GA ratios. Polymers obtained were characterized by FT-IR, GPC, ¹H-NMR and DSC. The lower critical solution temperature (LCST) of the copolymeric nanoparticles was 40±0.6 °C, the critical aggregation concentration (CAC) was 18 mg L⁻¹, and reversible change in nanoparticle size related to temperature was fluctuated between 210±10 and 109±26 nm, while change in zeta potential of the nanoparticles was between −36±6 and −26±4 mV. The transmission electron microscopy (TEM) images of nanoparticles were also presented.     

Synthesis of rapid responsive gels comprising hydrophilic backbone and poly(N-isopropylacrylamide) graft chains by RAFT polymerization and end-linking processes

A thermosensitive poly(N-isopropylacrylamide) (PNIPAM) grafted gel, which comprises hydrophilic backbone and freely mobile PNIPAM graft chains, was synthesized by reversible addition fragmentation chain transfer (RAFT) polymerization and end-linking processes. Functional PNIPAM bearing dithiobenzoate end group (-C(S)S-R) was prepared first, and then it was reacted with divinyl compounds to obtain gel. In order to adjust the composition of the gels, two divinyl compounds, N,N-methylenebisacrylamide (BIS) and poly(ethylene glycol) diacrylate (PEGDAC), were used. The cross-linking polymerization mechanism was proposed. The swelling and deswelling kinetics of the hydrogels were measured. The gels exhibit rapid deswelling kinetics. At the same time, they show rapid swelling kinetics within 30 min, whereas a conventional PNIPAM-co-PEG-co-BIS gel with the same feed composition requires more than 10 h to reach swelling equilibrium.     

Synthesis and characterization of biresponsive graft copolymer gels

Graft copolymer gels with different compositions were prepared by the radical polymerization of N-isopropylacrylamide (NIPAAm) and poly(2-vinylpyridine) (P2VP) macromonomers in dioxane with 1 mol% N,N′-methylenebisacrylamide (BIS) as the crosslinking agent. The graft copolymer gels were analyzed at different temperatures and pH values. They demonstrated the typical swelling behavior for poly(N-isopropylacrylamide) (PNIPAAm) gels with changing temperature. In addition to the temperature dependent measurements, the graft copolymer with a high P2VP content showed a pronounced swelling transition with changing pH value. By separating the temperature and the pH sensitive component, it was possible to obtain a gel which could be swelled independently in response to temperature and pH.     

Surface-initiated nitroxide-mediated radical polymerization of 2-(dimethylamino)ethyl acrylate on polymeric microspheres

2-(Dimethylamino)ethyl acrylate (DMAEA) was grafted from the surface of alkoxyamine-functionalized crosslinked poly(styrene-co-chloromethylstyrene) microspheres by nitroxide-mediated radical polymerization (NMRP). Latex particles (∼60 nm diameter) bearing chloromethyl groups were synthesized by emulsion polymerization. N-tert-butyl-N-(1-diethyl phosphono-2,2-dimethylpropyl)nitroxide (SG1) was then immobilized on the particle surface. Microspheres grafted with the homopolymer pDMAEA, as well as block copolymers poly(styrene-b-DMAEA) and poly(butyl acrylate-b-DMAEA) were prepared by surface-initiated NMRP in N,N-dimethylformamide at 112 °C, with the addition of free SG1 to ensure that control is maintained. Particle size increases with number average molecular weight (M_n) of untethered polymers. The polymerizations exhibit linear first order kinetic plots and slight curvature of evolution of M_n with conversion. The functional microspheres were analyzed by infrared spectroscopy, transmission electron microscopy and thermal analysis, as well as their dispersibility in water; the results support the formation of surface-grafted pDMAEA on the microspheres.     

Double-responsive core-shell-corona micelles from self-assembly of diblock copolymer of poly(t-butyl acrylate-co-acrylic acid)-b-poly(N-isopropylacrylamide)

Self-assembly of poly(t-butyl acrylate-co-acrylic acid)-b-poly(N-isopropylacrylamide) [P(tBA-co-AA)-b-PNIPAM], which was obtained from part hydrolysis of PtBA-b-PNIPAM synthesized by sequential atom transfer radical polymerization (ATRP) was studied. Thermo- and pH-responsive core-shell-corona (CSC) micelles with different structures were formed from (PtBA-co-PAA)-b-PNIPAM in aqueous solution. At pH 5.8 and 25 °C, the block copolymer self-assembled into spherical core-shell micelles with hydrophobic PtBA segments as the core, hydrophilic PAA/PNIPAM segments as the mixed shell. Increasing temperatures, core-shell micelles converted into CSC micelles with PtBA as the core, collapsed PNIPAM as the shell and soluble PAA as the corona. Moreover, decreasing pH at 25 °C, PAA chains collapsed onto the core resulting in CSC micelles with PtBA as the core, PAA as the shell and PNIPAM as the corona.     

Preparation and characterization of titanium dioxide core and polymer shell hybrid composite particles prepared by two-step dispersion polymerization

Titanium dioxide core and polymer shell composite poly (styrene-co-divinylbenzene)-methacrylic acid [P (St-co-DVB)-MAA]] particles were prepared by two-step dispersion polymerization. Fourier transform IR spectroscopy and elemental analysis were used to measure the content of methacrylic acid in composites particles. X-ray measurement photoelectron spectroscopy (XPS) measurements indicated the presence of an MAA unit on the surface of the composite particles. The combined results of the elemental analysis and the XPS measurements showed that the copolymer on the surface of poly (St-co-DVB)-MAA composite particles was rich in MAA compared with that in the interior of the composite particles. Field-emission scanning electron microscopy (FE-SEM) was used to study the morphology characterization. The composite particles produced showing good spectral reflectance compare with bare TiO₂. TGA results indicated that the encapsulation efficiency and estimated density of composite particles. Encapsulation of TiO₂ was up to 87.4% and the density was ranged from 1.78 to 2.06 g/cm³. Estimated density of the composite particles is suitable to 1.73 g/cm³, due to density matching with suspending fluid.     

Synthesis and properties of thermosensitive, crown ether incorporated poly(N-isopropylacrylamide) hydrogel

A crown ether derivative (4′-allyldibenzo-18-crown-6, CE) was covalently incorporated into the network of temperature sensitive poly(N-isopropylacrylamide) (PNIPA) hydrogels by copolymerization in a mixed solvent of water and tetrahydrofuran (H₂O/THF). The poly(N-isopropylacrylamide-co-4′-allyldibenzo-18-crown-6) (poly(NIPA-co-CE)) hydrogels exhibited dramatically faster deswelling rates than normal PNIPA hydrogels at a temperature (50 °C) above their lower critical solution temperatures. The effect of the solvent component ratio in the mixed solvent during the copolymerization on the swelling properties of the poly(NIPA-co-CE) hydrogel was investigated. The thermosensitive poly(NIPA-co-CE) hydrogels have potential applications in the extraction of cations and separation of chiral drugs.