Free Radical Polymerization Of Acrylamide Research Articles

Synthesis of cobalt nanoparticles in aqueous solutions assisted by polymer/inorganic hybrid

Hydrophilic polymer/inorganic hybrids (PIH) containing silica nanoparticles and polyacrylamide chains proved to be effective matrices for the in situ synthesis of cobalt nanoparticles. PIH sample was synthesized by free-radical polymerization of acrylamide from the unmodified surface of SiO2 nanoparticles and characterized by elemental analysis, dynamic thermogravimetric analysis, static light scattering, potentiometric titration, viscometry and transmission electron microscopy (TEM). The processes of borohydride reduction of cobalt ions from the Co(NO3)2·6H2O solution to nanoparticles in water medium and aqueous solutions of PIH were studied as a function of the concentrations of metal salt and hybrid concentrations using UV-Vis spectroscopy and TEM. A special approach to characterize the kinetics and efficiency of CoNPs formation in water medium and hybrid solutions using UV-Vis spectroscopy was implemented. The kinetic parameters of the CoNPs formation process as well as the yield, size, and morphology of nanoparticles in hybrid solutions and water medium at various concentrations of metal salt and hybrid were determined. The growth of both concentrations of reagents had a positive effect on the rate of formation of metal nanoparticles and their yield, but in all cases, the reduction process developed much slower in hybrid solutions compared to pure water. The morphology of the CoNPs/PIH nanocomposites was mainly represented by separate swollen hybrid particles containing metal nanoparticles with dav~3 nm.

High-strength self-healing hydrogels based on boronate-diol complexation cross-linking with good bioavailability

In this report, new self-healing hydrogels were obtained through simple one-pot free radical polymerization of acrylamide, phenylboronic acid, and 2-hydroxyethyl acrylate as copolymer monomers, potassium persulfate (KPS) as initiator, and tetramethylethylenediamine (TEMED) as promoter under low-temperature alkaline (pH = 9) conditions. The boronic acid group of phenylboronic acid (PBA) can interact with the hydroxyl group of hydroxyethyl acrylate (HEA) to form dynamic boronic ester bonds instead of the conventional bis acrylate crosslinkers. The effect of PBA content on the mechanical strength of the hydrogels was systematically investigated. The hydrogels exhibited higher stress, elongation, and self-healing properties due to the synergistic effect of H-bonds and boronate-diol complexation. Further studies revealed that the A–H–0.2–P–0.08 hydrogels exhibited excellent resistance to compression fatigue and also showed good biocompatibility through in vitro cytotoxicity tests.

Hyper strength, high sensitivity integrated wearable signal sensor based on non-covalent interaction of an ionic liquid and bacterial cellulose for human behavior monitoring.

Ion-sensing hydrogels exhibit electrical conductivity, softness, and mechanical and sensory properties akin to human tissue, rendering them an ideal material for mimicking human skin. In the realm of fabricating sensors for detecting human physiological activities, they present an ideal alternative to traditional rigid metal conductors. Nevertheless, achieving ionic hydrogels with outstanding tensile properties, toughness, ionic conductivity, and transport stability poses a significant challenge. This paper describes a simple method of forming a basic network by free radical polymerization of acrylamide, and then bacterial cellulose (BC) and 1-ethyl-3-methylimidazolium chloride ([EMIM]Cl) were introduced into the basic network. The polyhydrogen bonds and electrostatic interactions in the system gave the hydrogel notable tensile properties (3271 ± 37%), toughness (7.39 ± 0.13 MJ m-3), and high ultimate tensile stress (385.1 ± 7.2 kPa). In addition, the combination of BC and [EMIM]Cl collaboratively enhanced the mechanical properties and electrical conductivity. Ion sensing hydrogels have a wide operating strain range (≈1000%) and high sensitivity (gage factor (GF) = 11.85), and are therefore considered promising candidates for next-generation gel-based strain sensor platforms.

Synthesis and characterization of acrylamide/zeolite nanocomposite hydrogels for aqueous zinc-ion batteries

Polyacrylamide (PAM)/zeolite nanocomposite hydrogels were synthesized as novel gel polymer electrolytes (GPEs) for flexible zinc-ion batteries. The hydrogels were prepared by in-situ free radical polymerization of acrylamide in the presence of dispersed zeolite nanoparticles. Fourier transform infrared spectroscopy confirmed the formation of crosslinked PAM and its interaction with zeolite nanoparticles. Scanning electron microscopy revealed increased porosity and improved zeolite dispersion with higher nanoparticle content. Thermogravimetric analysis indicated enhanced thermal stability with zeolite incorporation. The compressive modulus increased from 0.25 MPa for the neat hydrogel to 1.12 MPa for the nanocomposite containing 20 wt% zeolite, demonstrating improved mechanical strength. Electrochemical impedance spectroscopy showed that the ionic conductivity increased from 0.75 mS/cm for pristine PAM hydrogel to 1.85 mS/cm for the nanocomposite hydrogel with 15 wt% zeolite, attributed to increased porosity and zeolite's ion-exchange capacity. Cyclic voltammetry revealed faster redox kinetics with increasing zeolite content. Galvanostatic cycling demonstrated that the PAM/zeolite nanocomposite GPE with 15 wt% zeolite delivered the optimal zinc-ion battery performance, with a high initial discharge capacity of 125 mAh/gZn, coulombic efficiency exceeding 98 %, and capacity retention of 87 % after 100 cycles. The results indicate that zeolite incorporation significantly enhanced the thermal, mechanical and electrochemical properties of the PAM hydrogels for application as GPEs for flexible zinc-ion batteries.

Multiple Hydrogen Bonding-Assisted High-Strength Hydrogel of Silica/Polyacrylamide Nanocomposite Cross-Linked with Polyethylenimine.

The nanocomposite gel system has been successfully applied as a water shutoff agent to enhance oil recovery (EOR) or for plugging to control lost circulation events. In this study, the silica/polyacrylamide nanocomposite was synthesized via in situ free radical polymerization of acrylamide (AM) monomers in the presence of silica nanoparticles. The composite was cross-linked with polyethylenimine to prepare a high-strength hydrogel. The viscosity test was conducted to determine the gelation time of the gel. Rheological measurements and sand pack breakthrough pressure tests were carried out to measure the gel strength. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) and scanning electron microscopy (SEM) tests were adopted to characterize the structure and morphology of the gel. The results show that compared to polyacrylamide (PAM) gel, the gelation time of the nanocomposite gel will decrease with increasing gel elasticity modulus, and the breakthrough pressure of the nanocomposite gel is 29.82 MPa, which increased by 65%. As shown in the ATR-FTIR test, this can be attributed to the presence of multiple hydrogen bonds for the PAM molecule with both silica and quartz sand particles. In the composite gel, hydrogen bonding mainly forms between the O atoms of PAM and the H atom on the surface of silica, enhancing gel strength and elasticity modulus with more cross-linking density and less porosity. Moreover, H bonding between additional -NH2 of PAM and quartz sand particles helps improve gel plugging pressure. However, in the silica and PAM mixture gel, the H bonding of silica occupies -NH2 of PAM, which became unavailable to attach on the sand surface, reducing the breakthrough pressure by 30%, although it can enhance the rheological strength. This study suggests that in situ composite of silica in PAM can not only greatly improve gel rheological strength but also help maintain the strong adhesion of PAM molecules onto quartz sand, resulting in better plugging performance in the sand reservoir.

Bioactive phosphate cross-linked guar gum-based hydrogels with enhanced mineralization ability for application in bone tissue engineering

Bioactive hydrogels have gained widespread recognition in bone tissue engineering due to their versatile physicochemical and biological attributes aligning with the requisite bone regeneration parameters. In this study, we explored a calcium-free phosphate approach to enhance the formation of bone-like apatite within phosphate cross-linked guar gum (GG)-based hydrogels (P-GG). P-GG hydrogels were developed using free radical polymerization of acrylamide (AM) monomer and bis[2-methacryloyloxy] ethyl phosphate (BMEP) as a cross-linker. The structure integrity and interactions of P-GG hydrogels were substantiated through fourier transform infrared (FTIR) and X-ray diffraction (XRD) analysis. The GG content significantly impacted the hydrogels porosity, pore size, and mechanical properties. The hydrogels displayed a porous structure with a fibrous topology similar to a ladder, allowing for better cell growth and adhesion. The phosphate functionality embedded within the hydrogel facilitated rapid biomineralization when exposed to simulated body fluid (SBF) solutions. This biomineralization of P-GG hydrogels in SBF solutions was validated through a combination of analytical techniques, including FTIR, XRD, field emission scanning electron microscopy (FE-SEM), and energy dispersive X-ray analysis (EDX). Together, the remarkable physical, chemical, and biological characteristics demonstrated by P-GG hydrogels emphasize their significant promise for use in the field of bone tissue engineering.

SPECTRAL AND PHOTOPHYSICAL CHARACTERISTICS OF ASYMMETRIC POLYMETHINE DYES IN POLYURETHANE MATRICES

Here the composite polymer sorbent hydrogels were synthesized by in situ technique via free radical polymerization of acrylamide (AAm), 2-hydroxyethyl methacrylate (2HEMA) and N,N’-methylene-bis(acrylamide) crosslinker mixture in the presence of as-prepared dispersion of nickel-aluminum layered double hydroxide (NiAl-LDH). A content of active NiAl-LDH filler in the polymer matrix was varied in a range of 30 – 70 wt.%. It was found a high filler content suppresses a molecular mobility of copolymer matrix chains and reduces a beginning of glass transition temperature of the polymer constituent. The results of thermal analysis of polymer composites demonstrate a high hydrophilicity level of polymer matrix and high solvation energy of polar functionalities by Н2О molecules that was concluded from slow moisture elimination process while the temperature grows up to 200–210 оС. Additionally, a dehydration process and changes in a structure of thermally labile filler were also observed at the same temperature interval. At higher temperatures a thermal degradation of polymer poly(AAm-co-2HEMA) matrix is carried out. When a temperature overcomes 400 оС the partially changed filler demonstrates a chemical interaction with degraded organic constituents of the composites and defined catalytic activity as well. Studying sorption activity of the composites shown that introducing NiAl-LDH into hydrophilic polymer matrix provides anion-exchange activity to the composite sorbents and, correspondingly, the ability to eliminate the anionic contaminants from aqueous media while the polymer matrix doesn’t absorb these substances at such conditions. The highest sorption capacity of 11,40 μmol/g against model contaminant – methyl orange dye was determined for composite sorbent with filler content of 70 wt. %. At the same time sorption capacity of NiAl-LDH filler in composite sorbents reduces from 25,7 to 16,6 μmol/g while a filler content grows from 30 to 70 wt.% as a result of filler particles aggregation processes during composites formation stage. To evaluate the ability of the composite sorbents to reuse the experiment of materials recycling was performed. It was stated out the using of anion-exchange technique and aqueous Na2CO3 solution as an efficient and non-hazardous eluent provides 80 % recovering efficiency of the active filler in the composites. It can be concluded the composite sorbents demonstrate a high overall efficiency and are valuable materials for practical application for decontamination of waste water.

Efficient Photocatalytic Degradation of Methylene Blue Dye from Aqueous Solution with Cerium Oxide Nanoparticles and Graphene Oxide-Doped Polyacrylamide.

A cerium oxide nanoparticles (CeO2-NPs)/graphene oxide (GO)/polyacrylamide (PAM) ternary composite was synthesized through free-radical polymerization of acrylamide in the presence of CeO2 nanoparticles and GO in an aqueous system. The synthesized composite material was characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) spectroscopy techniques and applied for the photocatalytic degradation of methylene blue (MB) dye from an aqueous solution. Tauc's model for direct transition was used to model for the optical band gap. The key operating parameters such as the amounts of CeO2-NPs and GO, pH, initial MB concentration, type of light irradiation, and contact time have been optimized to achieve the highest MB degradation percentage. The photocatalysis process was pH-dependent, and the optimum pH value was found to be 12.0. Under UV-A light, 90% dye degradation occurred in 90 min. The degradation of MB was also specified in terms of total organic carbon (TOC) and chemical oxygen demand (COD). Free-radical capture experiments were also performed to determine the role of radical species during the photocatalytic oxidation process. The photocatalytic process showed that the equilibrium data is in good agreement with the Langmuir-Hinshelwood kinetic model. A rate constant of 0.0259 min-1 was obtained. The hydrogel was also tested to assess its reusability, which is an important key factor in practical wastewater treatment. The photocatalytic activity only decreased to 75% after nine uses.

Fabrication porous adsorbents templated from aqueous foams using astragalus membranaceus and attapulgite as stabilizer for efficient removal of cationic dyes

The water-based foam stabilized by the natural surfactant applied in the fabrication of porous materials has attracted extensive attention, as the advantages of cleanness, convenience and low cost. Particularly, the development of a green preparation method has became the main research focus and frontier. In this work, a green liquid foam with high stability was prepared by synergistic stabilization of natural plant astragalus membranaceus (AMS) and attapulgite (APT), and then a novel porous material with sufficient hierarchical pore structure was templated from the foam via a simple free radical polymerization of acrylamide (AM). The characterization results revealed that the amphiphilic molecules from AMS adsorbed onto the water-air interface and formed a protective shell to prevent the bubble breakup, and APT gathered in the plateau border and formed a three-dimensional network structure, which greatly slowed down the drainage rate. The porous material polyacrylamide/astragalus membranaceus/attapulgite (PAM/AMS/APT) showed the excellent adsorption performance for cationic dyes of Methyl Violet (MV) and Methylene Blue (MB) in water, and the maximum adsorption capacity could reach to 709.13 and 703.30 mg/g, respectively. Furthermore, the polymer material enabled to regenerate and cycle via a convenient calcination process, and the adsorption capacity was still higher than 200 mg/g after five cycles. In short, this research provided a new idea for the green preparation of porous materials and the treatment of water pollution.

Effect of nano precipitated calcium carbonate on the properties of hydrogels prepared with acrylamide, starch, and TEMPO-oxidized nanocellulose

A variety of water-retaining hydrogels possessing macroporous interiors resembling a honeycomb framework were developed by free radical polymerization of acrylamide (AM), starch, and TEMPO-oxidized nanofibrillated cellulose (TONFC) (Poly (AM-co-TONFC/Starch) (PATS) hydrogels). With the help of ultrasound, nano precipitated calcium carbonate (NPCC) was gelatinized in the preformed NPCC suspension in a monomer solution that forms a hydrogel. When NPCC was dispersed in water, its surface was positively charged, and NPCC could be used as a condensation center to form hydrogen bonds with AM, TONFC, and starch, shortening the distance between AM, TONFC, and starch, increasing the pore size, and thinning the pore wall. The uniform dispersion of NPCC in hydrogels could also promote a more uniform degree of cross-linking in hydrogels. When the hydrogels was extruded and deformed by external forces, the stress of hydrogels was more uniform, so that they could withstand more forces without collapsing. When 4% NPCC was added (relative to starch and TONFC), the pore size of PATS2 hydrogel was uniformly distributed in the range of 10 to 20 μm. The maximum tensile strength of PATS2 hydrogel reached 84.8 KPa, and the elongation at break was 399%. The water absorption reached 172.3, and 65% water content was maintained after 720 h.

Synergies between polyacrylamide polymerization and nanoparticle generation using an atmospheric pressure plasma jet

AbstractWe performed a free radical polymerization of acrylamide in an aqueous solution by a radio frequency‐driven atmospheric pressure plasma jet. The polymerization was catalyzed by simultaneous generation of nanoparticles resulting in a percentage polymer yield increased by a factor of 2–30 times. Polyacrylamide acted as a capping agent for the silver nanoparticle formation yielding smaller nanoparticles while uncontrolled growth and massive particles were observed without acrylamide for the same conditions. Both Fourier transform infrared and Raman spectroscopy show the formation of bonds of (poly)acrylamide with the silver particles suggesting that polymerization at least in part occurs at the surface of silver particles. As plasma enables reduction without the addition of chemicals, this procedure might be a novel biocompatible approach to generate polyacrylamide/silver nanocomposite hydrogels.

Triblock Superabsorbent Polymer Nanocomposites with Enhanced Water Retention Capacities and Rheological Characteristics.

Superabsorbent polymers (SAPs) are useful polymers in a wide range of application fields ranging from the hygiene industry to construction and agriculture. As versatility and high water absorption capacity are their important merits, SAPs usually suffer from low water retention capacity (fast release) and weak mechanical properties. To address these drawbacks, a set of new superabsorbent polymer–Halloysite nanotube (HNT) nanocomposites was synthesized via free radical polymerization of acrylamide, 2-acrylamido-2-methylpropane-1-sulfonic acid, and acrylic acid in the presence of vinyltrimethoxysilane (VTMS) as the crosslinker. FTIR and TGA characterizations confirm the polymerization of SAP and successful incorporation of HNTs into the SAP polymer matrix. The effect of the HNT nanofiller amount in the nanocomposite polymer matrix was investigated with swelling–release performance tests, crosslink density calculations, and rheology measurements. It was found that equilibrium swelling ratios are correlated and therefore can be tuned via the crosslink densities of nanocomposites, while water retention capacities are governed by storage moduli. A maximum swelling of 537 g/g was observed when 5 wt % HNT was incorporated, in which the crosslink density is the lowest. Among the SAP nanocomposites prepared, the highest storage modulus was observed when 1 wt % of nanofiller was incorporated, which coincides with the nanocomposite with the longest water retention. The water release duration of SAPs was prolonged up to 27 days with 1% HNT addition in parallel with the achieved maximum storage modulus. Finally, three different incorporation mechanisms of the HNT nanofiller into the SAP nanocomposite structure were proposed and confirmed with rheology measurements. This study provides a rapid synthesis method for SAP nanocomposites with enhanced water retention capacities and explains the relationship between swelling and crosslink density and water retention and mechanical properties of SAP nanocomposites.

Experimental Study on High-Performers Quaternary Copolymer Based on Host-Guest Effect.

A quaternary polymer (HGP) was prepared by the free-radical polymerization of acrylamide, acrylic acid, maleic anhydride functionalized β-cyclodextrin (MAH-β-CD), and N-(3-methacrylamidopropyl)-N, N-dimethylnaphthalen-1-aminium chloride (NAP). It was found that host–guest behavior occurred most effectively at a molar rate of NAP and CD with 1:1, which exhibited better solubility than hydrophobically associative polymer. Moreover, the as-prepared polymer has superior salt tolerance, shear resistance, and viscoelasticity due to host–guest strategy. More importantly, the HGP solution simulates the distribution of formation water in the Bohai SZ1-1 oilfield has good rheological properties at 120 °C. All results show that the proposed polymer could be a competitive candidate in oilfield applications such as fracturing fluids, displacement fluids, and drilling fluids.

Synthesis, Characterization of P(CH/AA-co-AM) and Adsorptive Removal of Pb (II) ions from Aqueous Solution: Thermodynamic Study

Cross-linking Chitosan/Poly (Acryl amide-Acrylic acid) Hydrogel (P(CH/AA-co-AM)) synthesized via free radical polymerization of Acrylamide and acrylic acid as monomers after that addition chitosan, using MBA and KPS as initiator. The produced materials' structural, surface, and thermal properties were determined using the following techniques: FT-IR, TGA, TEM, and FE-SEM. This study is concerned with a significant application of surface chemistry in the fields of removing heavy metals. It deals with the adsorption-systems of Pb (II) on Cross-linking Chitosan / Poly (Acrylic acid-Acryl amide) Hydrogel at variable conditions of concentration and temp. The measured data are following the Freundlich equation and, according to the Giles classification, the adsorption isotherms are of type S3. As a temperature feature (10, 20, 25 and 30oC), adsorption was investigated. With increasing temperature (endothermic process), the extent of adsorption of Pb (II)on P(CH / AA-co-AM) was found for increase. They have also measured the essential thermodynamic functions.

Enhanced toughness of ultra-fine sulphoaluminate cement-based hybrid grouting materials by incorporating in-situ polymerization of acrylamide

Deep coal mining requires grouting reinforcement materials with adjustable setting time, high early strength and toughness. Sulphoaluminate cement-based grouting materials (SCGM) have been widely used due to their low cost, but still suffer from poor deformation and toughness. To solve this problem, in-situ polymerization of acrylamide was developed to modify SCGM, and the effects of acrylamide addition on the fluidity, setting time, mechanical properties, and microstructure evolution of SCGM were systematically investigated. The results indicated that the addition of acrylamide significantly improved the toughness of SCGM. When the acrylamide content reached 35 wt%, the flexural strength of SCGM increased to 10 MPa and the compressive strength reached 35 MPa. In light of microstructural analysis, the exothermic heat of SCGM hydration promoted the free radical polymerization of acrylamide to form inorganic–organic hybrid grouting material with a three-dimensional interpenetrating network structure, which was responsible for the enhanced toughness of SCGM. Those results provided a new method to enhance the toughness of SCGM, making it more suitable for grouting reinforcement engineering.

A hydrolytically stable amide polar stationary phase for hydrophilic interaction chromatography

A novel amide functionalized polar stationary phase has been described by grafting acrylamide polymer coating onto hydrolysed poly (glycidyl methacrylate-divinylbenzene) (GMA-DVB) microsphere. The grafting of acrylamide coating is performed via free radical polymerization of acrylamide with pendant double bonds of hydrolysed GMA-DVB microsphere. The obtained stationary phase (G-pAM) possesses favorable hydrophilicity, as proved by strong retention and good separation ability towards several types of model polar analytes (e.g. 71913 plates/m plate count of sucrose), and excellent hydrolytically stability, as indicated by extremely low bleed level (much superior to commercial ones, ~23.7-fold–~77.4-fold lower). Negligible baseline drift under gradient elution (water fraction even up to 50%) was observed. It also exhibits good selectivity in the separation of isomers and homologue sugars.

Preparation of polyglycidyl methacrylate microspheres and nanocomposite hydrogels crosslinked by hydrogen bonds

In order to meet the application of the flexible wings of the submersible, nanocomposite hydrogels(NC gels) was prepared. Preparation of polyglycidyl methacrylate (PGMA) microspheres and correspondingly NC gels were reported. PGMA microspheres were prepared and modified by N-Methyl-D-glucamine, followed by free radical polymerization of acrylamide in the presence of microspheres to construct nanocomposite hydrogel. FT-IR, XPS and DLS verified a successful introduction of hydroxyl groups during modification. The effects of the particle size and content of the microspheres on the swelling properties of the composite hydrogels were investigated. Hydrogen bonds between hydroxyl groups and polyacrylamide molecular chains play important roles to the swelling property of NC gels. The intermolecular interaction and the crosslinking density were enhanced by the hydrogen bonds, and resultantly, swelling ratio of NC gels decreases.

Halloysite nanotubes@polydopamine reinforced polyacrylamide-gelatin hydrogels with NIR light triggered shape memory and self-healing capability

In this study, the polyacrylamide-gelatin composite hydrogels reinforced by halloysite nanotubes@polydopamine (HNTs@PDA) with NIR triggered shape memory performance and self-healing capacity were prepared through in-situ free radical polymerization of acrylamide in the mixture of Laponite-RD, HNTs@PDA and gelatin. HNTs@PDA was firstly synthesized through oxidative polymerization of dopamine on the surfaces of HNTs. HNTs@PDA was characterized by transmission electron microscopy, scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, Zeta potential, particle size analysis, and X-ray photoelectron spectroscopy. The photothermal performance of HNTs@PDA was then determined and the results reveal that HNTs@PDA can be employed as a superior photothermal agent to prepare light responsive hydrogels. The structure, morphology, mechanical properties, NIR triggered shape memory performance and self-healing capacity of the composite hydrogels were studied. The modified nanotubes act as cross-linking agent of polyacrylamide to form a rigid network in the hydrogel matrix, which leads to a significant increase in the mechanical properties. Moreover, the NIR triggered shape recovery process of the hydrogel is quite rapid, for example, it is only 63 s for recovering 720° shape change for the hydrogel of HNTs@PDA 40. The maximum NIR triggered healing efficiency of the hydrogels can reach 76%. The HNTs@PDA reinforced hydrogels with superior mechanical properties, NIR triggered shape memory, and self-healing ability exhibit promising applications in biomedical materials and smart engineering materials.

Novel Polyacrylamide/Polypyrrole Hydrogel for Electrically Controlled Release of Salicylic Acid

Polyacrylamide/polypyrrole (PAM/PPy) hydrogel was developed for the application in controlled drug delivery. PAM/PPy hydrogel was synthesized via free-radical polymerization of acrylamide using ammonium persulfate (APS) as initiator in the dispersion of PPy nanoparticle. N,N’-methylenebisacrylamide (MBA) and N,N,N’,N’-tetra-methylenediamine (TEMED) were utilized as cross-linker and accelerator, respectively. Salicylic acid (SA) was selected as a model drug in this work. The effect of PPy contents on SA-loading and releasing performances was investigated. The more PPy content was incorporated, the greater SA-loading and releasing were found. This is attributed to the increasing pore size of the PAM hydrogel when PPy nanoparticles were incorporated. Drug releasing performance from the SA-loaded PAM/PPy hydrogel were controllable under the applied potential of 1.0 volt. The research exhibits the potential of using conductive polymer hydrogel to control the drug release rate at an optimal desired level.

Synthesis, characterization and rheological properties of acrylamide/ acidic monomer/ N-(4-ethylphenyl) acrylamide Terpolymers as pH- responsive hydrogels and nanogels

ABSTRACTNovel pH-responsive superabsorbent hydrogels (HGs) and nanogels (NGs) with high water uptake and adjustable viscoelastic behavior were synthesized by free radical polymerization of acrylamide (AM) and a small amount of N-(4-ethylphenyl)acrylamide (EΦAM) hydrophobic comonomer in the presence of three different acidic monomers. Structure of the synthesized linear terpolymers was investigated by 1H-NMR spectroscopy. The solution viscosity of the linear terpolymers was measured at different pH and temperatures, where AM-EΦAM-AMPS terpolymer showed higher viscosity in different conditions. Equilibrium swelling ratio (ESR) of hydrogels was studied using response surface methodology and empirically modeled as a function of pH and temperature as stimuli.