A facile preparation of pH‐temperature dual stimuli‐responsive supramolecular hydrogel and its controllable drug release

A series of pH‐temperature dual stimuli‐responsive random copolymers poly[N,N‐dimethylaminoethyl methacrylate‐co‐poly(poly(ethylene glycol) methyl ether methacrylate][poly(DMAEMA‐co‐MPEGMA)] were synthesized by free radical polymerization. The supramolecular hydrogel was formed by pseudopolyrotaxane, which was prepared with the host‐guest interactions between α‐cyclodextrin (α‐CD) and poly(ethylene glycol) (PEG) side chains. Fourier transform infrared (FT‐IR), nuclear magnetic resonance (¹H NMR), and X‐ray diffraction (XRD) confirmed the structures of the hydrogels. The pH‐temperature dual stimuli responsive properties of the hydrogels were characterized by rheometer. Finally, the controllable drug release behavior of the hydrogel, which was used 5‐fluorouracil (5‐Fu) as the model drug, was investigated at different temperatures and different pH values. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43279.     

Preparation and drug‐release behavior of minocycline‐loaded poly[hydroxyethyl methacrylate‐co‐poly(ethylene glycol)–methacrylate] films

In this work, biocompatible hydrogel matrices for wound‐dressing materials and controlled drug‐release systems were prepared from poly[hydroxyethyl methacrylate‐co‐poly(ethylene glycol)–methacrylate] [p(HEMA‐co‐PEG–MA] films via UV‐initiated photopolymerization. The characterization of the hydrogels was conducted with swelling experiments, Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis (differential scanning calorimetry), and contact‐angle studies. The water absorbency of the hydrogel films significantly changed with the change of the medium pH from 4.0 to 7.4. The thermal stability of the copolymer was lowered by an increase in the ratio of poly(ethylene glycol) (PEG) to methacrylate (MA) in the film structure. Contact‐angle measurements on the surface of the p(HEMA‐co‐PEG–MA) films demonstrated that the copolymer gave rise to a significant hydrophilic surface in comparison with the homopolymer of 2‐hydroxyethyl methacrylate (HEMA). The blood protein adsorption was significantly reduced on the surface of the copolymer hydrogels in comparison with the control homopolymer of HEMA. Model antibiotic (i.e., minocycline) release experiments were performed in physiological buffer saline solutions with a continuous flow release system. The amount of minocycline release was shown to be dependent on the HEMA/PEG–MA ratio. The hydrogels have good antifouling properties and therefore are suitable candidates for wound dressing and other tissue engineering applications. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Design of hemocompatible poly(DMAEMA‐co‐PEGMA) hydrogels for controlled release of insulin

This works aims at (i) studying the antiadhesive properties and the hemocompatibility of poly[2‐(dimethylamino)ethyl methacrylate]‐co‐poly[(ethylene glycol)methacrylate] [poly(DMAEMA‐co‐PEGMA)] copolymers and (ii) investigating the insulin delivery kinetics through hydrogels at physiological pH. A series of poly(DMAEMA‐co‐PEGMA) hydrogels have been synthesized, and their controlled composition was confirmed by X‐ray photoelectron spectroscopy. Then, antibiofouling properties of hydrogels—fibrinogen, erythrocytes, and thrombocytes adhesion—are correlated to their molecular compositions through their hydrophilic properties. As DMAEMA/PEGMA ratio of 70/30 (D70) offers the best compromise between pH sensitivity and hemocompatibility, it is selected for investigating the kinetic rate of insulin release at physiological pH, and the diffusion coefficient of insulin in gel is found to be 0.64 × 10^?7 cm² s^?1. Overall, this study unveils that poly(DMAEMA‐co‐PEGMA) copolymers are promising hemocompatible materials for drug delivery systems. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42365.     

Swelling behaviour of a new kind of polyampholyte hydrogel composed of dimethylaminoethyl methacrylate and acrylic acid

Poly[(dimethylaminoethyl methacrylate)‐co‐(acrylic acid)] [poly(DMAEMA‐co‐AAc)] hydrogels have been synthesized by UV‐induced copolymerization of dimethylaminoethyl methacrylate (DMAEMA) and acrylic acid monomer. The effects of pH and ionic strength on the swelling behaviour of poly(DMAEMA‐co‐AAc) hydrogels were investigated in detail. It was found that there is minimal equilibrium swelling ratio (ESR) for the hydrogels with the change of pH, and the pH at minimal ESR of the hydrogels was defined by the isoelectric points (IEP), similar to the situation with protein molecules. The IEP of the hydrogels shifted to higher values with increase in the DMAEMA content in the hydrogels. Antipolyelectrolyte behaviour of the hydrogels at a pH near the IEP was observed as well, and the ESR increased with increasing ionic strength. The study of swelling kinetics of the hydrogels showed that the swelling process was Fickian at the IEP and non‐Fickian when the pH deviated from the IEP. Copyright © 2003 Society of Chemical Industry     

Fluconazole release through semi‐interpenetrating polymer network hydrogels based on chitosan,acrylic acid,and citraconic acid

Semi‐interpenetrating polymer network hydrogels with different compositions of chitosan (Cs), acrylic acid, and citraconic acid were synthesized via free‐radical polymerization with ethylene glycol dimethacrylate as a crosslinker. The variations of the swelling percentages of the hydrogels with time, temperature, and pH were determined, and Cs–poly(acrylic acid) (PAA) hydrogels were found to be most swollen at pH 7.4 and 37°C. Scanning electron micrographs of Cs–PAA and Cs–P(AA‐co‐CA)‐1 (Cs‐poly(acrylicacid‐co‐citraconir acid)^?1) were taken to observe the morphological differences in the hydrogels. Although the less swollen hydrogel, Cs–P(AA‐co‐CA)‐1, had a sponge‐type structure, the most swollen hydrogel, Cs–PAA, displayed a uniform porous appearance. Fluconazole was entrapped in Cs–P(AA‐co‐CA)‐1 and Cs–PAA hydrogels, and the release was investigated at pH 4.0 and 37°C. The kinetic release parameters of the hydrogels (the gel characteristic constant and the swelling exponent) were calculated, and non‐Fickian diffusion was established for Cs–PAA, which released fluconazole much more slowly than the Cs–P(AA‐co‐CA)‐1 hydrogel. A therapeutic range was reached at close to 1 h for both hydrogels. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Effect of the anionic‐group/cationic‐group ratio on the swelling behavior and controlled release of agrochemicals of the amphoteric,superabsorbent polymer poly(acrylic acid‐co‐diallyldimethylammonium chloride)

A series of amphoteric, superabsorbent polymers [poly(acrylic acid‐co‐diallyldimethylammonium chloride)] with different molar ratios of anionic groups to cationic groups were prepared by solution polymerization to investigate their swelling behaviors and the controlled release of agrochemicals. Various factors, including the solution pH, the concentrations of different salt solutions, and the temperature, were studied. The dynamic parameters of hydrogels at different temperatures suggested that diffusion was Fickian at lower temperatures, whereas non‐Fickian diffusion prevailed at higher temperatures. A copolymer hydrogel with a low anionic‐group/cationic‐group ratio showed a higher swelling capacity in water and higher salt tolerance. Also, the anionic‐group/cationic‐group ratio was not the dominant factor in determining the water retention. A poly(acrylic acid‐co‐diallyldimethylammonium chloride) hydrogel could control the release of agrochemicals effectively. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 986–991, 2006     

Poly(N‐isopropylacrylamide‐co‐sodium acrylate) hydrogels: Interactions with surfactants

Poly(N‐isopropylacrylamide‐co‐sodium acrylate) [poly(NIPAM‐co‐SA)] hydrogels were modified with three different kind of surfactants (cationic, anionic, and nonionic) to study the effect on the swelling properties. The structural variation of the surfactant‐modified hydrogels was investigated in detail. The interaction between the surfactants and the hydrogel varies and strictly depends on the surfactant type. The variation in thermal stability of the modified surfactant hydrogels was investigated and compared with unmodified hydrogel. Further, the hydrogel swelling/diffusion kinetic parameters were investigated and diffusion of water into hydrogel was found to be of the non‐Fickian transport mechanism. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3423–3430, 2007     

A novel temperature and pH dual‐responsive hybrid hydrogel with polyhedral oligomeric silsesquioxane as crosslinker: synthesis,characterization and drug release properties

Octavinyl polyhedral oligomeric silsesquioxane (OVPS) is used as the crosslinker instead of N,N′‐methylenebisacrylamide (BIS) to copolymerize with 2‐(dimethylamino)ethyl methacrylate (DMAEMA) or DMAEMA and N‐isopropylacrylamide (NIPAM) to prepare hybrid hydrogels: P(OVPS‐co‐DMAEMA) and P(OVPS‐co‐DMAEMA‐co‐NIPAM). The prepared hydrogels are transparent and show dual response to temperature and pH. The hydrogels were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, X‐ray diffraction, differential scanning calorimetry, thermogravimetric analysis, dynamic mechanical analysis and tensile tests. Their mechanical properties, swelling ratio, deswelling and reswelling behaviors as well as drug release properties were investigated. The results indicate that OVPS can be incorporated into polymer networks in proportion to feed ratios. The P(OVPS‐co‐DMAEMA) hydrogel exhibits more homogeneous interior structure, higher swelling ratio and faster response than the conventional hydrogel prepared with BIS. Moreover, the incorporation of OVPS enhances the compression and tensile properties of the hydrogels. The feed ratios of OVPS and NIPAM have a great effect on volume phase transition temperature, thermal sensitivity, swelling behavior, mechanical properties and drug release properties of the hybrid hydrogels. The prepared dual‐responsive OVPS‐containing hydrogels are expected to be used as biomedical materials in drug release and tissue engineering. © 2014 Society of Chemical Industry     

pH‐sensitive swelling and release behaviors of anionic hydrogels for intelligent drug delivery system

The pH‐sensitive swelling and release behaviors of the anionic P(MAA‐co‐EGMA) hydrogels were investigated as a biological on–off switch for the design of an intelligent drug delivery system triggered by external pH changes. There was a drastic change of the equilibrium weight swelling ratio of P(MAA‐co‐EGMA) hydrogels at a pH of around 5, which is the pK_a of poly (methacrylic acid) (PMAA). At a pH below 5, the hydrogels were in a relatively collapsed state but at a pH higher than 5, the hydrogels swelled to a high degree. When the molecular weight of the pendent poly(ethylene glycol) (PEG) of the P(MAA‐co‐EGMA) increased, the swelling ratio decreased at a pH higher than 5. The pK_a values of the P(MAA‐co‐EGMA) hydrogels moved to a higher pH range as the pendent PEG molecular weight increased. When the feed concentration of the crosslinker of the hydrogel increased the swelling ratio of the P(MAA‐co‐EGMA) hydrogels decreased at a pH higher than 5. In release experiments using Rhodamine B (Rh‐B) as a model solute, the P(MAA‐co‐EGMA) hydrogels showed a pH‐sensitive release behavior. At low pH (pH 4.0) a small amount of Rh‐B was released while at high pH (pH 6.0) a relatively large amount of Rh‐B was released from the hydrogels. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Temperature‐responsiveness and sustained delivery properties of macroporous PEG‐co‐PNIPAAm‐co‐PCL hydrogels

A series of novel thermosensitive macroporous poly (ethylene glycol) (PEG)‐co‐poly(N‐isopropylacrylamide) (PNIPAAm)‐co‐poly (ε‐caprolactone) (PCL) hydrogels were synthesized via in situ free radical polymerization. Poly(ethylene glycol diacrylate) (PEGDAc) and poly(ε‐caprolactone diacrylate) (PCLDAc) were prepared as macrocrosslinkers. All compounds were investigated by Nuclear Magnetic Resonance (NMR) and Fourier transform‐infrared spectroscopy (FT‐IR). Differential Scanning Calorimetry (DSC) results showed the lower critical solution temperatures (LCSTs) of the gels were at around 31°C. The macroporous gels not only had considerable swelling ratios, but also exhibited rapid swelling kinetics and response sensitivity. Above mentioned hydrogels showed a remarkable oscillatory swelling–deswelling transition, making them have potential application in long‐term drug delivery. POLYM. ENG. SCI., 55:223–230, 2015. © 2014 Society of Plastics Engineers     

Relaxational behavior and swelling‐pH master curves of poly[(diethylaminoethyl methacrylate)‐graft‐(ethylene glycol)] hydrogels

Poly[(diethylaminoethyl methacrylate)‐graft‐(ethylene glycol)] hydrogels were prepared with a molar ratio of 10:1 of diethylaminoethyl methacrylate to poly(ethylene glycol) of number‐average molecular weights (M_n) 200, 400 and 1000 g mol^?1 using tetra(ethylene glycol) dimethacrylate to give a crosslinking ratio between 0.5 and 4.0 %. Glucose oxidase and catalase were immobilized in the matrix during polymerization. The maximum enzyme loading used was 6.6 × 10^?4 g of glucose oxidase per g of polymer. The equilibrium and dynamic swelling properties of these hydrogels were investigated. The pH‐dependent equilibrium swelling characteristics showed a sharp transition between the swollen and the collapsed state at pH 7.0. The dynamic response of the hydrogel discs to pH was analyzed in pulsatile pH conditions. The effects of particle size, crosslinking and molecular weight of poly(ethylene glycol) (PEG) on the dynamic swelling response were investigated. The pulsatile nature of the response was analyzed using Boltzmann superposition. Swelling–pH master curves were obtained. Copyright © 2004 Society of Chemical Industry     

Synthesis,Characterization, and drug release study of acrylamide‐co‐itaconic acid based smart hydrogel

A new kind of pH and temperature responsive poly(acrylamide‐co‐itaconic acid) hydrogel was prepared by free radical polymerization using ammonium persulfate as initiator and different comonomer ratios. The hydrogels were characterized in terms of chemical composition, swelling‐deswelling behavior, morphology, crystallographic behavior, and drug release properties. All the hydrogels showed high swelling ability in aqueous solutions, the maximum being at pH 7. Swelling decreased on either side of pH 7 (i.e., both in acidic and alkaline region) and increased with increase in temperature. The hydrogel with 10 mol% itaconic acid (IA) absorbed maximum water among the copolymer gels. The cellular structures of the hydrogels were clearly revealed by microscopic analysis and SEM pictures. Swelling of the gels in water followed non‐Fickian type of diffusion principle. The hydrogel was proved to be a controlled release vehicle, for example in drug delivery by using its smart properties. The hydrogel with 10 mol% IA also absorbed maximum amount of drug (ascorbic acid) under study. Incorporation of drug in hydrogel matrix was established from XRD peak analysis. POLYM. ENG. SCI., 55:113–122, 2015. © 2014 Society of Plastics Engineers     

Control release of some pesticides from starch/(ethylene glycol‐co‐methacrylic acid) copolymers prepared by γ‐irradiation

Starch/(Ethylene glycol‐co‐Methacrylic acid) [Starch/(EG‐co‐MAA)] hydrogels were designed for controlled delivery of pesticides, such as Fluometuron (FH); Thiophanate Methyl (TF) and Trifluralin (TI) which are use in the agricultural field. The delivery device was prepared by using γ‐irradiation and was characterized by FTIR, DSC, and SEM. The swelling behavior of hydrogels as a function of copolymer composition and irradiation dose was detected. This article discusses the swelling kinetics of polymer matrix and release dynamics of Trifluralin from hydrogels for the evaluation of the diffusion mechanism and diffusion coefficients. The values of the diffusion exponent ‘n’ for both the swelling of hydrogels and the release of Trifluralin from the hydrogels have been observed between 0.56 and 0.86 when the MAA content in the polymers was varied from 20 to 80 wt %, respectively. It is inferred from the values of the ‘n’ that non‐Fickian diffusion mechanism has occurred for different EG/MAA compositions. The release rate from matrices prepared under different conditions was studied to determine which factors have the most affect and control over the hydrogel matrix release property. The preparation conditions such as EG/MAA hydrogel composition, pesticide concentration, type of pesticide and irradiation dose greatly affect the pesticide release rate, which also influenced by the pH and temperature of the matrix‐surrounding medium. The pesticide release rate decreased as the irradiation dose and pH increased, but it increased as the MAA content, pesticide concentration and temperature increased. The release rate of Trifluralin is the highest one, whereas the Fluometuron is the lowest. The properties of the prepared hydrogels may make them acceptable for practical use as bioactive controlled release matrices. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Swelling behavior of poly(acrylamide‐co‐N‐vinylimidazole) hydrogels under different environment conditions

A series of random copolymers of acrylamide and N‐vinylimidazole, poly(AAm‐co‐NVI), with various compositions were prepared using redox copolymerization. The influence of environmental conditions such as pH, temperature, and ionic strength on the swelling behavior of the copolymeric hydrogels was investigated. The hydrogels exhibited the highest equilibrium swelling in basic medium at high temperature. Equilibrium swelling decreased with rising ionic strength at pH 5.0. As pH increased, equilibrium swelling of the hydrogels increased at pH 11.0 and I = 0.20 M. Swelling kinetics of the hydrogels was found to be non‐Fickian at 25°C. The process tended to be Fickian at higher pH and temperature. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1783–1788, 2005     

Synthesis and characterization of a porous poly(hydroxyethylmethacrylate‐co‐ethylene glycol dimethacrylate)‐based hydrogel device for the implantable delivery of insulin

Poly(hydroxyethylmethacrylate‐co‐ethylene glycol dimethacrylate) [poly(HEMA‐co‐EGDMA)]‐based hydrogel devices were synthesized by a free‐radical polymerization reaction with 2‐hydroxyethylmethacrylate as the monomer, different concentrations of ethylene glycol dimethacrylate (EGDMA) as the crosslinking agent, and ammonium persulfate/N,N,N′,N′‐tetra‐methyl ethylenediamine as the free‐radical initiator. The porosity of the poly(HEMA‐co‐EGDMA) hydrogels was controlled with water as the porogen. The Fourier transform infrared spectrum of poly(HEMA‐co‐EGDMA) showed absorption bands associated with ? C?O stretching at 1714 cm^?1, C? O? C stretching vibrations at 1152 cm^?1, and a broad band at 3500–3800 cm^?1 corresponding to ? OH stretching. Atomic force microscopy studies showed that the hydrogel containing 67% water had pores in the range of 3500–9000 nm, whereas the hydrogel containing 7% water did not show measurable pores. The hydrogel synthesized with 1% EGDMA showed 50% thallium‐201 release within the first 30 min and about 80% release within 60 min. In vitro insulin‐release studies suggested that the hydrogel with 27% water showed sustained release up to 120 min, whereas the hydrogels with 47 and 67% water showed that nearly all of the insulin was released within 60 min. Hydrogel devices synthesized with 27% water and filled with insulin particles showed sustained release for up to 8 days, whereas the hydrogels synthesized with 47 and 67% water released insulin completely within 3 days of administration. Animal studies suggested that the hydrogel devices synthesized with 27% water and filled with insulin‐loaded particles (120 IU) were able to control blood glucose levels for up to 5 days after implantation. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Environmental responses of poly(N‐isopropylacrylamide‐co‐glycidyl methacrylate derivatized dextran) hydrogels

A series of intelligent hydrogels (poly(NIPA‐co‐GMA‐Dex)) were synthesized by copolymerization of N‐isopropylacrylamide (NIPA) and glycidyl methacrylate derivatized dextran (GMA‐Dex) in aqueous solution with different ratios. Their swelling behaviors at different temperatures and in different pH and ionic strengths, and their mechanical properties were studied. It has found that poly(NIPA‐co‐GMA‐Dex) hydrogels are temperature‐, pH‐, and ionic strength‐sensitive associated with the roles of the component PNIPA and GMA‐Dex, respectively. Most significantly, poly (NIPA‐co‐GMA‐Dex) hydrogels exhibit simultaneously good swelling properties and mechanical properties. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2435–2439, 2005     

A comparative study of swelling properties of hydrogels based on poly(acrylamide‐co‐methyl methacrylate) containing physical and chemical crosslinks

Poly (acrylamide‐co‐methyl methacrylate) hydrogels of different ratios were prepared by using chemical and physical crosslinks to study the effect of nature of crosslinks on swelling behavior of hydrogels. The chemically crosslinked gels were prepared by using NN′‐methylene bis acrylamide, while physically crosslinked hydrogels were prepared by precipitation polymerization method, using dioxane as solvent. Detailed swelling kinetics such as swelling ratio, transport exponent n, diffusion coefficient D and the effect of pH on equilibrium swelling studies. The study revealed that the nature of crosslinks alter the swelling characteristics of the hydrogel. In chemically crosslinked hydrogels the water transport is Fickian in nature, while in the case of the physically crosslinked hydrogels the water transport mechanism is anomalous indicating major change in relaxation mechanism due to nature of crosslinks. The results also indicate that with increasing acrylamide content the swelling ratio of the hydrogels were also increased, but the transport exponent n remains nearly constant. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 779–786, 2003     

Swelling,pH sensitivity,and mechanical properties of poly(acrylamide‐co‐sodium methacrylate) nanocomposite hydrogels impregnated with carboxyl‐functionalized carbon nanotubes

A series of novel nanocomposite hydrogels were prepared by a cross‐linking copolymerization method. Structural and morphological characterizations of the nanocomposite hydrogels revealed that a good compatibility exists between poly(acrylamide‐co‐sodium methacrylate) [P(AM‐co‐SMA)] and carboxyl‐functionalized carbon nanotubes (MWNTs–COOH). The P(AM‐co‐SMA)/MWNTs–COOH nanocomposite hydrogels with a suitable MWNTs–COOH loading exhibited better swelling capability, higher pH sensitivity, good reversibility, and repeatability, and rapid response to external pH stimuli, compared with the P(AM‐co‐SMA). The compression mechanical tests revealed that the nanocomposite hydrogel displayed excellent compressive strengths and elastic mechanical properties, with higher ultimate compressive stress, and meanwhile still retain a good recoverable strain in the presence of MWNTs–COOH. These excellent properties may primarily be attributed to effectively dispersing of a suitable MWNTs–COOH loading into the matrix of the polymers and formation of additional hydrogen bonds. The nanocomposite hydrogels were expected to find applications in drug controlled release and issue engineering. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers     

Electrical actuation of electroresponsive hydrogels based on poly(acrylamide‐co‐acrylic acid)/graphite suitable for biomedical applications

A pH‐sensitive composite hydrogel based on poly(acrylamide‐co‐acrylic acid)/graphite was prepared by solution polymerization process in presence of redox initiator potassium persulfate/N,N,N′,N′‐tetramethylethylenediamine and cross‐linker (ethylene glycol dimethylacrylate). The structures of the hydrogels were confirmed using Fourier transform infrared, X‐ray diffraction, and scanning electron microscopy (SEM) study. Tensile strengths of the hydrogels were determined by using a universal tensile machine, whereas the electrical conductivities of the hydrogels were evaluated using Four‐probe method. The influence of cross‐linker, graphite content, and temperature on the conductivity of the hydrogel was also investigated. The bending behavior of the conducting hydrogels was investigated by exposing the hydrogels under electric field in aqueous medium. By studying the swelling ratio of the polymer synthesized under different conditions, optimization conditions were found for a polymer with the highest swelling ratio. Also, the hemolytic potentiality test revealed that prepared hydrogels are biocompatible in nature. POLYM. COMPOS., 35:27–36, 2014. © 2013 Society of Plastics Engineers     

Swelling behavior of semi‐interpenetrating polymer network hydrogels composed of poly(vinyl alcohol) and poly(acrylamide‐co‐sodium methacrylate)

Interpenetrating polymer network (IPN) hydrogels based on poly(vinyl alcohol) (PVA) and poly(acrylamide‐co‐sodium methacrylate) poly(AAm‐co‐SMA) were prepared by the semi IPN method. These IPN hydrogels were prepared by polymerizing aqueous solution of acrylamide and sodium methacrylate, using ammonium persulphate/N,N,N¹,N¹‐tetramethylethylenediamine (APS/TMEDA) initiating system and N,N¹‐methylene‐bisacrylamide (MBA) as a crosslinker in the presence of a host polymer, poly(vinyl alcohol). The influence of reaction conditions, such as the concentration of PVA, sodium methacrylate, crosslinker, initiator, and reaction temperature, on the swelling behavior of these IPNs was investigated in detail. The results showed that the IPN hydrogels exhibited different swelling behavior as the reaction conditions varied. To verify the structural difference in the IPN hydrogels, scanning electron microscopy (SEM) was used to identify the morphological changes in the IPN as the concentration of crosslinker varied. In addition to MBA, two other crosslinkers were also employed in the preparation of IPNs to illustrate the difference in their swelling phenomena. The swelling kinetics, equilibrium water content, and water transport mechanism of all the IPN hydrogels were investigated. IPN hydrogels being ionic in nature, the swelling behavior was significantly affected by environmental conditions, such as temperature, ionic strength, and pH of the swelling medium. Further, their swelling behavior was also examined in different physiological bio‐fluids. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 302–314, 2005