High‐temperature resistant superabsorbent based on poly(acrylic acid) with triallylammonium chloride as crosslinking agent

A novel high‐temperature resistant superabsorbent was prepared by solution polymerization of partially neutralized acrylic acid (AA), using triallylammonium chloride as crosslinker, potassium persulfate as initiator. The factors that influence the water‐absorbing capacity at 25 and 200°C such as mass concentration of monomer, mass ratio of crosslinker to AA, mass ratio of initiator to AA, and neutralization degree were investigated. The structure of the superabsorbent was characterized by Fourier transform infrared, thermogravimetric analysis, and scanning electron microscopy. The optimum conditions were obtained and the swelling ratios in distilled water and 1 wt % of NaCl solution could reach 841 and 74 g/g at 300°C, respectively. The superabsorbent also showed high swelling rate and good salt resistance. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41243.     

Effective removal of a cobalt‐tetrasulfonated phthalocyanine dye from an aqueous solution with a novel modified chitosan‐based superabsorbent hydrogel

Industrial wastewaters from the Merox process are heavily polluted by toxic cobalt‐tetrasulfonated phthalocyanine (CoTsPc) dye catalyst, and in this article, we describe the synthesis of novel chitosan hydrogels and their adsorption capabilities against CoTsPc as biosorbents. In this study, novel chitosan hydrogels were crosslinked by 3,3′,4,4′‐tetracarboxybenzophenone dianhydride and used for the first time. The adsorption capacities of the hydrogels were significantly improved, and they exhibited excellent sorption behavior with ammonium sulfate modification. The adsorption behavior was observed to be pH dependent, and the optimum pH was found to be 8. Moreover, the swelling studies indicated that the hydrogels are superabsorbent. The reusability of these dye‐adsorbent hydrogels was also evaluated. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46167.     

A study on environment‐friendly polymer gel for water shut‐off treatments in low‐temperature reservoirs

In this study, the zirconium acetate crosslinked gel systems are studied owing to their environment‐friendly and gelation performance in low‐temperature reservoirs through rheological measurements, environmental scanning electron microscopy, and scanning electron microscopy. The effects of various parameters on the gelation properties, stability, and microstructure in bottle test and porous media were addressed. With the increase of concentrations and temperature, gelation time is reduced and gel strength is increased. In addition, the gel systems show salt tolerance and shearing resistance. The environment‐friendly gel systems have a high stability in both injection water and formation water. A three‐dimensional network structure was formed in the gel and confirmed by environmental scanning electron microscopy. The three‐dimensional gel network was also formed in porous media, which bridges across the pore throats and reduced the water permeability in the formation. This study suggests that environment‐friendly polymer gels can be used for water shut‐off treatments in low‐temperature reservoirs. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40154.     

Gelation performance of poly(ethylene imine) crosslinking polymer–layered silicate nanocomposite gel system for potential water‐shutoff use in high‐temperature reservoirs

Polymer gels have been widely used for water shutoff in mature oil fields. In this paper, polyacrylamide (PAM)–montmorillonite (MMT) nanocomposites (NC) were prepared through in situ intercalative polymerization. Fourier transform infrared spectroscopy and X‐ray diffraction were conducted to characterize the prepared PAM/MMT nanocomposites. The gelation performance of poly(ethylene imine) (PEI) crosslinking PAM/MMT nanocomposite gel system (NC/PEI gel system) was systematically investigated by bottle testing and viscosity measurement methods. The results showed that the gelation performance of the NC/PEI gel system was greatly affected by the total dissolved solids, PAM/MMT nanocomposite concentration, and PEI concentration. The NC/PEI gel system exhibited much better thermal stability and gelation performance than the PAM/PEI gel system at the same conditions. The gelation performance after flowing through porous media of the NC/PEI gel system before injection and that of the subsequently injected gel system was different. The gel strength decreased and the gelation time was delayed after the gel system before injection was flowed through porous media. However, the gel strength of the subsequently injected gel system did not decrease, and only the gelation time was delayed after flowing through porous media. This study suggests that the NC/PEI gel system can be used as a potential water‐shutoff agent in high‐temperature reservoirs. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44243.     

Gellan gum–O,O′‐bis(2‐aminopropyl)‐polyethylene glycol hydrogel for controlled fertilizer release

A gellan gum–Jeffamine superabsorbent hydrogel was obtained with different crosslink densities using different amounts of (1‐ethyl‐3‐(3‐dimethylaminopropyl)carbodiimide hydrochloride) and N‐hydroxysuccinimide. Infrared spectroscopy and thermal analysis confirm the crosslinking. A morphology analysis indicates denser structures for samples with higher crosslinking points. The swelling degree in high‐acyl gellan gum hydrogels was equivalent to 145 times their dry weight, and 77 times when low‐acyl gellan gum was used. Hydrogels also showed a 450 min water retention, as opposed to 280 min for pure water, evidencing good humidity control, suitable for use in arid climates. They also demonstrated a maximum release of commercial fertilizer of about 400 mg per gram for KH₂PO₄ and about 300 mg per gram for NPK 20‐5‐20. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45636.     

Preparation of biphenyl‐bridged,crosslinked polyalkoxysilanes: Determination of oil/organic solvent absorption features

A novel type of biphenyl‐bridged alkoxysilane‐based crosslinked polyalkoxysilane was prepared by the condensation of 4,4′‐bis(triethoxysilyl)?1,1′‐biphenyl and different lengths of linear aliphatic diols. Fourier transform infrared spectroscopy, solid‐state ¹³C and ²⁹Si cross‐polarization magic angle spinning nuclear magnetic resonance, and thermogravimetric analysis were used to characterize the biphenyl‐bridged, crosslinked polyalkoxysilanes. The crosslinked polymers were found to have very quick and high swelling capabilities in organic solvents and oils. The absorption–desorption kinetics and reusability features of the crosslinked polymers were also studied, and we found that the synthesized polymers reached their maximum absorption capacity during a variety of tests without losing capacity. We also tested the absorption performance of the sorbents from water surfaces. All of these results confirm that biphenyl‐bridged, crosslinked polyalkoxysilanes could be good candidates as sorbent materials for the cleaning of water from organic contaminants. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44193.     

New insights into phenol–formaldehyde‐based gel systems with ammonium salt for low‐temperature reservoirs

Polymer gels are effective tools that are still widely used in mature oilfield development to stop unwanted fluid production from oil and gas wells, but conventional gelant formulations have become increasingly difficult to apply at low and ultralow temperatures. Because of this situation, the gelation performance of phenol–formaldehyde‐based gel systems at a low temperature of 25°C is discussed in this article. The results show that the gelation time and strength of the gel systems can be perfectly controlled by the adjustment of the polymer concentration, the molecular weight, the crosslinking agent concentration, the ammonium salt concentration, and the composition. The polymer concentration and molecular weight can affect not only the gelation time and the gel strength but also its stability. The ammonium salt concentration affected not only the gelation time but also its viscosity before a detectable gel formed. Among them, the polymer concentration was the most important factor affecting the gel stability. For low‐temperature reservoirs, the phenol–formaldehyde‐based gel system achieved a much longer gelation time. Polymer gels formulated with a combination of 0.2–0.4 wt % polymer, 0.5–1.0 wt % formaldehyde or phenol–formaldehyde, and 0.1–0.6 wt % ammonium salt, and we added 0.02–0.03 wt % resorcinol to provide a gelation time between 2 h and 2 days. The maximum gel strength reached code I. The results of this study suggest that the formaldehyde‐based gel system could be used effectively in low‐temperature reservoirs. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40657.     

Fast‐swelling superabsorbent polymers with polymerizable macromolecular surfactant as crosslinker

Fast‐swelling superabsorbent polymers (SAPs) have been prepared by micellar cross‐linking copolymerization of acrylic acid and acrylamide using polymerizable macromolecular surfactants (PMSs) as multifunctional crosslinkers, with a foaming technique. Sodium bicarbonate (NaHCO₃)/acetone and Pluronic F127 were used as foam (or porosity) generators and stabilizer, respectively. It has been found that the PMSs with different polyethylene glycol (PEG) chain length have little effect on the swelling rate of the SAPs, while the foam generators are crucial. In addition, the monomer concentration and the concentration of the PMS are important to the fast swelling rate of the SAPs. For a balance of a relatively fast‐swelling rate, high water absorbency under load and low cost in drying, a monomer concentration of above 50%, 0.08% PMS, and 5% NaHCO₃ are preferable. The water absorbency of SAP prepared under optimal conditions could reach half of equilibrium water absorbency in 30 seconds and the saline water absorbency under load could reach 18.4 g/g. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44173.     

Preparation,water absorbency,and enzyme degradability of novel chitin‐ and cellulose/chitin‐based superabsorbent hydrogels

Superabsorbent hydrogels were prepared from chitin dissolved in lithium chloride and N‐methyl‐2‐pyrrolidinone by esterification crosslinking with 1,2,3,4‐butanetetracarboxylic dianhydride (BTCA). The absorbency of the chitin hydrogel was strongly dependent on the ratio of BTCA feed to chitin. The hydrogel prepared at the feed ratio of 5 showed the highest absorbency (345 g/g‐polymer), and the hydrogel was composed of 0.65 molecules of BTCA per monomer unit of chitin. The hydrogels exhibited good biodegradability by chitinase with a maximum degradation of 91% within 7 days. This method for obtaining the chitin hydrogel was also applicable to cellulose and chitin mixtures, and 1 : 1 cellulose/chitin hybrid hydrogels could be obtained by the esterification crosslinking of a mixture with a 1 : 1 molar ratio of cellulose and chitin. The optimal BTCA feed ratio of 5 resulted in the cellulose/chitin hydrogel with the highest water absorbency (329 g/g‐polymer), and the hydrogel contained 0.65 molecules of BTCA per polysaccharide monomer unit. In addition, the hybrid hydrogels were degraded by cellulase as well as chitinase. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Nitrofurazone‐loaded PVA–PEG semi‐IPN for application as hydrogel dressing for normal and burn wounds

Hydrogels have been used in a wide variety of biomedical devises, particularly in the field of drug delivery, tissue engineering, and wound healing. In this study, a polyvinyl alcohol (PVA)–polyethylene glycol (PEG) semi‐interpenetrating hydrogel network (IPN)‐based wound dressing system containing nitrofurazone (NFZ) was synthesized by chemical crosslinking technique. The introduction of PEG to PVA matrix led to reduction in the water vapor transmission rate, which in‐turn resulted in improved healing activity. Drug‐loaded IPNs were prepared by mixing aqueous solution of NFZ with the optimized PVA–PEG formulation subsequent to the crosslinking step. The in vitro diffusion studies of NFZ indicated a relatively slow release of drug resulting from its microencapsulation in the polymeric matrix. Subsequently, in vivo wound healing efficacy toward acute and burn wound healing in experimental rats was investigated. Semi‐IPN hydrogel loaded with NFZ dressing improved the overall healing rate in both acute and burn wounds, as evidenced by significant increase in total protein, hydroxyproline and hexosamine contents. Histological examinations also correlated well with the biochemical findings. A faster wound contraction was also observed in hydrogel treated acute and burn wounds. The results indicated that PVA–PEG semi‐IPN hydrogel based dressing systems containing NFZ could be used as an effective wound dressing material. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis and properties of a superabsorbent from an ultraviolet‐irradiated waste nameko mushroom substrate and poly(acrylic acid)

To better use the waste nameko mushroom substrate (WNMS) and prevent its pollution into the environment, a novel superabsorbent polymer was synthesized via the UV irradiation copolymerization of acrylic acid and WNMS in the presence of an initiator (dimethoxy‐2‐phenylacetophenone and ammonium persulfate) and crosslinker N,N′‐methylenebisacrylamide. The factors that had an influence on the water absorbency of the superabsorbent polymer were investigated and optimized. Under the optimized conditions, WNMS–poly(acrylic acid) was obtained. Its swelling behaviors, which followed the pseudo‐second‐order swelling kinetic model, were investigated in distilled water (1701 g/g) and a 0.9 wt % NaCl solution (388 g/g). The water absorbency was 1011 g/g in a 0.1 wt % urea solution and 80% amount of urea diffused into the gels. The urea diffusion followed a Fickian diffusion mechanism. Moreover, the product showed excellent water retention capabilities under the condition of high temperature or high pressure. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40471.     

Evaluation of pH‐sensitive hydrogels to control the permeability anisotropy of oil reservoirs

In stratified or fractured oil reservoirs, the oil recovery efficiency tends to be low as the injected fluid flows mainly through the matrix's most permeable regions, leaving behind part of the displaceable oil in the matrix's unswept zones. Given this issue, this study aims to evaluate the potential of applying seven commercial samples, based on poly(acrylic acid), to control the anisotropic permeability profile of reservoirs. To perform this study, first, continuous and oscillatory shear tests were conducted to characterize the hydrogel's rheological and viscoelastic behavior in various subsurface conditions (salinity, temperature, and/or pH value). Second, polymer dispersion elution tests were performed in a porous medium to evaluate the matrix's permeability reduction after treatment with hydrogels. The seven commercial samples were classified as pseudoplastic fluids at pH values ranging from 1 to 10. Under typical reservoir conditions, PAAr 70 (which has intermediate molar mass and intermediate number of crosslinks) was the only sample to behave as a strong gel (G′/G″ > 10). Elution tests confirmed that the PAAr 70 hydrogel gelified inside the consolidated sandstone plugs and reduced the matrix's permeability four‐fold. Therefore, samples based on poly(acrylic acid) with high crosslink density proved to be the most promising for controlling the anisotropic permeability profile of heterogeneous oil reservoirs. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40665.     

Enhanced swelling and methylene blue adsorption of polyacrylamide‐based superabsorbents using alginate modified montmorillonite

Polyacrylamide/sodium alginate modified montmorillonite (PAM/SA‐MMT) superabsorbent composites were synthesized by free‐radical polymerization under normal atmospheric conditions. They were characterized by X‐ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy (FTIR). Their water absorbency and methylene blue (MB) adsorption behaviors were studied. Compared with PAM/MMT composites, PAM/SA‐MMT composites demonstrated greater water absorbency (863 g g^?1 in distilled water and 101 g g^?1 in 0.9 wt % NaCl solution) and higher adsorption capacity of 2639 mg g^?1 for MB. The adsorption behaviors of the composites showed that the isotherms and adsorption kinetics were in good agreement with the Langmuir equation and pseudo‐second‐order equation, respectively. FTIR analysis suggested that the MB adsorption of PAM/SA‐MMT composites via a mechanism combined electrostatic, H‐bonding and hydrophobic interaction. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014 , 131, 40013.     

Water‐soluble allyl and diallyl camphor sulfonamides‐based polyacrylamide copolymers for enhanced oil recovery

The monomers N‐allyl camphor sulfonamide (CSAP) and N,N‐diallyl camphor sulfonamide (CSDAP) were copolymerized with acrylamide (AM), acrylic acid (AA) for EOR, respectively. The effect of the synthesis conditions on apparent viscosity was investigated, and the copolymers were characterized by Fourier transform infrared spectroscopy (FTIR), ¹H nuclear magnetic resonance (¹H NMR), environmental scanning electron microscope (ESEM), and thermogravimetric analysis (TGA). Increasing mass ratio of diallyl CSDAP could lead to the water‐insoluble of copolymer, and competition of free radicals could make polymerization of AM/AA/CSDAP more difficult than AM/AA/CSAP. The thickening function and temperature resistance of two copolymers were remarkably improved in comparison with similar molecular weight partially hydrolyzed polyacrylamide (HPAM). In addition, the pronounced temperature resistance of the copolymers has been also demonstrated by temperature resistance test. It has also found that copolymers AM/AA/CSAP and AM/AA/CSDAP brine solutions could obtain significant enhanced oil recovery at 70°C suggesting their potential being applied in chemical enhanced oil recovery. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41238.     

pH‐sensitive crosslinked guar gum‐based superabsorbent hydrogels: Swelling response in simulated environments and water retention behavior in plant growth media

Crosslinked guar gum‐g‐polyacrylate (cl‐GG‐g‐PA) superabsorbent hydrogels were prepared to explore their potential as soil conditioners and carriers. The hydrogels were prepared by in situ grafting polymerization and crosslinking of acrylamide onto a natural GG followed by hydrolysis. Microwave‐initiated synthesis under the chosen experimental conditions did not exhibit any significant improvement over the conventional technique. The optimization studies of various synthesis parameters, namely, monomer concentration, crosslinker concentration, initiator concentration, quantity of water per unit reaction mass, particle size of backbone, and concentration of alkali were performed. The hydrogels were characterized by wide‐angle X‐ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and solid‐state ¹³C‐NMR spectroscopy. Swelling behavior of a candidate hydrogel [GG‐superabsorbent polymer (SAP)] in response to external stimuli, namely, salt solutions, fertilizer solutions, temperature, and pH, was studied. The GG‐SAP exhibited significant swelling in various environments. The effect of GG‐SAP on water absorption and the retention characteristics of sandy loam soil and soil‐less medium were also studied as a function of temperature and moisture tensions. The addition of GG‐SAP significantly improved the moisture characteristics of plant growth media (both soil and soil‐less), showing that it has tremendous potential for diverse applications in moisture stress agriculture. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41060.     

Experimental research of hydroquinone (HQ)/hexamethylene tetramine (HMTA) gel for water plugging treatments in high‐temperature and high‐salinity reservoirs

Polymer gel, as a water plugging treatment agent, has been successfully used in enhanced oil recovery (EOR) of mature oil fields. A new thermal‐resistance and salt‐tolerance polymer gel was developed based on HPAM and HQ/HMTA under the condition of high‐temperature (100.8 °C) and high‐salinity (up to 19.8 × 10⁴ mg/L and Ca²⁺&Mg²⁺ 0.8 × 10⁴ mg/L). The influence factors of gelling performance and coreflood performances were studied, the microstructure of the gel was observed with the environmental scanning electron microscopy, and gelation mechanism was proposed to illuminate the detailed gelation process. The gelation time decreases and the gel strength increases with the increase of polymer concentration, crosslinker concentration, or temperature. Although shearing had a negative effect on the viscosity of gelling solution, the gel strength, and the stability of gel have not been affected. The gelling solution has a good ability of injection and could selectively flow into high permeable zone. Additionally, the plugging rate increases and stays above 85% with the increase of the permeability or the gel strength. The microstructure of the gel confirms that the gel formed a three‐dimensional network structure. Based on the microstructure and the reaction process of the gel, a possible gelation mechanism is proposed. This study suggests that the gel system can be used in harsh reservoir conditions and the gelation time and gel strength can be controlled with adjusting the formation rate and the concentration of crosslinking agents. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44359.     

Swelling behavior of novel protein‐based superabsorbent nanocomposite

A novel superabsorbent nanocomposite based on hydrolyzed collagen was synthesized by simultaneously graft copolymerization of 2‐acrylamido‐2‐methylpropane sulfonic acid (AMPS) and acrylamide (AAm). Sodium montmorilonite (Na‐MMt) was used as clay. Methylenebisacrylamide (MBA) and ammonium persulfate (APS) were used as crosslinker and initiator, respectively. The effect of reaction variables such as nanoclay content, MBA and APS concentrations as well as the AMPS/AAm weight ratio on the water absorbency of nanocomposites was investigated. Although the water absorbency was decreased by increasing of MBA concentration, an optimum swelling capacity was achieved for clay, APS, and AMPS/AAm variables. The structure of nanocomposite was identified using FTIR spectroscopy, XRD patterns, and scanning electron microscopy graphs. The effect of swelling media comprising various dissolved salts and different pHs was studied. Also, water retention capacity was studied, and the results showed that inclusion of Na‐MMt nanoclay causes an increase in water retention under heating. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Boric acid incorporated on the surface of reactive nanosilica providing a nano‐crosslinker with potential in guar gum fracturing fluid

Small molecule borate crosslinker widely used in hydraulic fracturing treatment has a low crosslinking efficiency of less than 1%. Thus boric acid was introduced onto the surface of reactive nanosilica (denoted as nano‐SiO₂; size: about 20 nm) containing ? NH₂ group to obtain a nanosilica‐based crosslinker (denoted as nano‐crosslinker) with increased crosslinking efficiency, thereby broadening the application of nano‐SiO₂ in guar gum fracturing fluid. Moreover, the influence of the as‐prepared nano‐crosslinker on the rheological behavior of guar gum gel was investigated with borate crosslinker as a reference. Results show that boric acid chemically reacts with the amino group of the reactive nano‐SiO₂ to form N? B bond, which is beneficial to the formation of the network structure of guar gum gel. The guar gum gel crosslinked with the 57 ppm of borate based on the carrier of nano‐SiO₂ exhibits better temperature tolerance and shear resistance as well as breaking behavior than the counterpart crosslinked with 200 ppm of borate. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45037.     

Self‐healing hydrogel of poly(vinyl alcohol)/graphite oxide with pH‐sensitive and enhanced thermal properties

Supramolecular hydrogel is a fascinating polymeric material composed of three‐dimensional noncovalent networks with many outstanding properties, especially reversible relevant performances. A self‐healing supramolecular hydrogel of poly(vinyl alcohol)/graphite oxide, with reversible pH responsiveness and good thermal stability, was prepared. The morphology, functional group changes, swelling performance, thermal stability, rheological performance, and self‐healing property of the PVA/GO hydrogel were investigated. A probable mechanism between the components and potential applications were also examined in our study. The experimental results show that the PVA/GO hydrogel was not only self‐healable without external stimulus or addition of any healing agents, but also pH sensitive and with good thermal stability. Green ingredients (PVA and GO) and a simple synthesis method (a freezing/thawing treatment) may pose little threat to the environment and also promote the production of such hydrogels. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46143.     

Synthesis and swelling properties of a pH‐ and temperature‐dual responsive hydrogel by inverse microemulsion polymerization

A novel pH‐ and temperature‐dual responsive hydrogel was synthesized by inverse microemulsion polymerization, using itonic acid (IA) as pH‐responsive monomer, N‐isopropylacrylamide (NPAM) as thermo‐responsive monomer and acrylamide (AM) as the nonionic hydrophilic monomer. Factors affecting water and salt absorption, as well as swellability of the dual responsive hydrogels, such as IA/NPAM mass ratio and crosslinker amount, were investigated. pH‐ and temperature‐sensitivity and dynamic viscoelasticity behaviors of the dual responsive hydrogels were also studied. The dual responsive responsive hydrogels showed suitable water and salt absorbency, remarkable pH‐, and temperature‐sensitivity, adjustable swellability and enhanced viscoelastic behaviors under high stress. Water absorbency and pH‐sensitivity increased while salt absorbency and temperature‐ sensitivity decreased with increasing IA/NIPAM mass ratio. Both water absorbency and salt absorbency increased first with crosslinker amount increased to 0.2 wt %, and then decreased with increasing crosslinker amount. Temperature‐induced shrinkage range of the dual responsive hydrogels was higher and broader than that of the conventional poly(N‐isopropylacrylamide) hydrogel. TEM indicated that the as‐synthesized hydrogel particles were regular and spherical‐like in shape and had the mean particle size of 49nm in the range of 30–78 nm. FTIR indicated the structure of the dual responsive hydrogels. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42139.