Thermosensitive Poly[(2‐(diethylamino)ethyl methacrylate)‐co‐(N,N‐dimethylacrylamide)] Cryogels Prepared by a Two‐Step Polymerization Method

Summary: Temperature‐sensitive P(DEAEMA‐co‐DMAAm) cryogels with five different DMAAm contents were synthesized via a two‐step polymerization method, the initial polymerization being conducted for various times at 22 °C, followed by polymerization at ?26 °C for 24 h. The influence of the first‐step time and the content of DMAAm on the swelling ratio and network parameters such as the polymer/solvent interaction parameter, the average molecular mass between crosslinks, and the mesh size of the cryogels were reported and discussed. The swelling studies indicated that the swelling increased in the following order: 22C45 > 22C30 > 22C15 > 22C0. The cryogels exhibited swelling/deswelling transitions (reentrant phenomena) in water depending on temperature. These properties were attributed to the macroporous and regularly arranged network of the cryogels. Scanning electron microscope graphs reveal that the macroporous network structure of the cryogels can be adjusted by applying a two‐step polymerization.

Chemical structure of the P(DEAEMA‐co‐DMAAm) cryogels.     

Synthesis and characterization of fast responsive thermo‐ and pH‐sensitive poly[(N,N‐diethylacrylamide)‐co‐(acrylic acid)] hydrogels

BACKGROUND: A considerable amount of research has been focused on smart hydrogels that can respond to external environmental stimuli, especially temperature and pH. In this study, fast responsive thermo‐ and pH‐sensitive poly[(N,N‐diethylacrylamide)‐co‐(acrylic acid)] hydrogels were prepared by free radical copolymerization in aqueous solution using poly(ethylene glycol) (PEG) as a pore‐forming agent. RESULTS: Swelling studies showed that the hydrogels produced had both temperature and pH sensitivity. The deswelling kinetics at high temperature demonstrated that the shrinking rates were influenced by the addition of the pore‐forming agent and the amount of acrylic acid in the initial total monomers. The deswelling curves in low‐buffer solutions had two stages. Pulsatile swelling studies indicated that the PEG‐modified hydrogels were superior to the normal ones. These different swelling properties were further confirmed by the results of scanning electron microscopy. CONCLUSION: Such fast responsive thermo‐ and pH‐sensitive hydrogels are expected to be useful in biomedical fields for stimuli‐responsive drug delivery systems. Copyright © 2008 Society of Chemical Industry     

External Stimuli‐Responsive Characteristics of Ionic Poly[(N,N‐diethylaminoethyl methacrylate)‐co‐(N‐vinyl‐2‐pyrrolidone)] Hydrogels

Summary: Polyelectrolyte hydrogels containing diprotic acid moieties sensitive to ionic strength changes of the swelling medium were synthesized from N,N‐diethylaminoethyl methacrylate (DEAEMA), N‐vinyl‐2‐pyrrolidone (VP) and itaconic acid (IA) by using ammonium persulfate (APS) as a free radical initiator in the presence of the cross‐linker, methylenebisacrylamide (MBAAm). The swelling behavior of the ionic poly[(N,N‐diethylaminoethyl methacrylate)‐co‐(N‐vinyl‐2‐pyrrolidone)] [P(DEAEMA/VP)] hydrogels were investigated in pure water; in NaCI solutions with pH 4 and 9; and in water‐acetone mixtures depending on the IA content in the hydrogel. The average molecular mass between cross‐links ( ) and polymer‐solvent interaction parameter (χ) of the hydrogels were determined from equilibrium swelling values. The pulsatile swelling behavior was also observed in response to solvent changes between the solution in water and in acetone. The equilibrium swelling ratio of these hydrogels was basically unaffected with change in temperature. The swelling variations were explained according to the swelling theory based on the hydrogel chemical structure.

Pulsatile swelling behavior of ionic P(DEAEMA/VP) hydrogels in response to solvent changes between water and acetone at 25 °C.     

Relation between microstructure and glass transition temperature of poly[(methyl methacrylate)‐co‐(ethyl acrylate)]

The glass transition temperature of a series of samples of the poly[(methyl methacrylate)‐co‐(ethyl acrylate)] copolymer, synthesized at low conversion, were calculated theoretically using the equations of Barton and Johnston. The values obtained are more precise when the probabilities of the compositional diads are derived from the ¹³C NMR data instead of the classical method utilizing reactivity ratios. This can be observed more clearly when the copolymer samples are synthesized at high conversion. Introduction of configuration (tacticity) at the diad level confirms the above observations and slightly improves the calculated values of T_g compared to the initial formulae which were only taking into account the compositional sequences of the copolymer. © 2001 Society of Chemical Industry     

Swelling and Adsorption Properties of Hydrophobic Poly[(N‐(3‐(dimethylamino)propyl)methacrylamide)‐co‐(lauryl acrylate)] Hydrogels in Aqueous Solutions of Surfactants

Summary: The swelling and adsorption behavior of a series of hydrophobic poly[(N‐(3‐(dimethylamino)propyl)methacrylamide)‐co‐(lauryl acrylate)] [P(DMAPMA‐co‐LA)] hydrogels was studied as a function of temperature in aqueous solutions of the anionic surfactant sodium dodecyl sulfate (SDS) and the cationic surfactant dodecyltrimethylammonium bromide (DTAB). Between 0 and 41.7 mol‐% of lauryl acrylate (LA) were used as a hydrophobic comonomer in the hydrogel synthesis. In SDS solutions, the equilibrium swelling ratio of the hydrogels decreased with increasing temperature. At SDS concentrations below 0.0083 M , the hydrogels exhibited an almost linear swelling behavior. However, for SDS concentrations above 0.0083 M , non‐linear swelling behavior was observed in the range 28–36 °C. In contrast to the SDS solutions, in all DTAB solutions the equilibrium swelling ratio of the hydrogels increased with increasing temperature and a positive temperature sensitive property was shown for all P(DMAPMA‐co‐LA) hydrogels. The adsorption capacities of the hydrogels in aqueous solutions of SDS and DTAB were determined via surface tension measurements. An increase in the LA content in the hydrogel caused an increase in the amount of adsorbed surfactant molecules in both media.

Effect of the DTAB concentration on the adsorption capacities of P(DMAPMA‐co‐LA) hydrogels.     

DNA adsorption on poly(N,N‐dimethylacrylamide)‐grafted chitosan hydrogels

In this study, poly(N,N‐dimethylacrylamide) grafted chitosan (PDMAAm‐g‐CT) hydrogels were prepared for deoxyribonucleic acid (DNA) adsorption. Instead of directly grafting the N,N‐dimethylacrylamide (DMAAm) monomer onto the chitosan (CT) chains, poly(N,N‐dimethylacrylamide) with carboxylic acid end group (PDMAAm‐COOH) was firstly synthesized by free‐radical polymerization using mercaptoacetic acid (MAAc) as the chain‐transfer agent and then grafted onto the CT having amino groups. The synthesis of PDMAAm‐COOH and its grafting onto the CT chains were confirmed by attenuated total reflectance Fourier transform infrared (ATR‐FTIR) spectroscopy. From gel permeation chromatography measurements, the number‐average molecular weight (M _n) and polydispersity index of PDMAAm‐COOH were found as 2400 g/mol and 2.3, respectively. The PDMAAm‐g‐CT hydrogels were utilized as the adsorbents in DNA adsorption experiments conducted at +4°C in a trisEDTA solution of pH 7.4. The hydrogels produced with higher PDMAAm‐COOH content exhibited higher DNA adsorption capacity. The DNA adsorption capacity up to 4620 μg DNA/g dry gel could be achieved with the PDMAAm‐g‐CT hydrogels prepared in 80.0 wt % PDMAAm‐COOH feed concentration. This value is approximately seven times higher than that of CT alone. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Surface‐active amphiphilic poly[(2‐acrylamido‐2‐methylpropanesulfonic acid)‐co‐(N‐isopropylacrylamide)] nanoparticles as stabilizer in aqueous emulsion polymerization

This work reports the effect of nanogel solid particles on the surface and interfacial tension of water/air and water/styrene interfaces. Moreover, the work aimed to use nanogels as a stabilizer for miniemulsion aqueous polymerization. A series of amphiphilic crosslinked N‐isopropylacrylamide (NIPAm) and 2‐acrylamido‐2‐methylpropanesulfonic acid (AMPS) copolymer nanogels were synthesized based on an aqueous copolymerization batch method. Divinylbenzene and N,N‐methylene bisacrylamide were used as crosslinkers. The morphologies of the prepared nanogels were investigated using transmission and scanning electron microscopies. The lower critical transition temperatures were determined using differential scanning calorimetry. The surface tension of colloidal NIPAm/AMPS dispersions was measured as functions of surface age, temperature and the morphology of the NIPAm/AMPS nanogels. The NIPAm/AMPS nanogels reduced the surface tension of water to about 30.1 mN m^?1 at 298 K with a small increase at 313 K. Surface activities of these nanogels in water were determined by surface tension measurements. The NIPAm/AMPS dispersions had high surface activity and were used as a stabilizer to prepare a crosslinked poly(styrene‐co‐AMPS) microgel based on emulsion crosslinking polymerization. © 2013 Society of Chemical Industry     

Kinetics of solvent responsiveness in poly(N,N‐dimethylacrylamide) hydrogels of different morphology

Crosslinked poly(N,N‐dimethylacrylamide) hydrogel samples were synthesized with various total comonomer concentrations and crosslinker ratios in the reacting mixture, and at two different temperatures: room temperature and the boiling point of the reacting mixture, about 80 °C. During gelation of samples prepared at the higher temperature, the bubbles of the boiling system were trapped in positions homogeneously distributed, and post‐gel reactions fixed them. These samples were macroporous, showing about three times the swelling capacity of conventional hydrogels synthesized at room temperature with the same composition. Both types of hydrogel swollen at equilibrium in water deswelled exponentially with time when they were immersed in acetone or dioxane. The rate of shrinking was higher for macroporous than for conventional samples and it was smaller in dioxane, the solvent with higher viscosity (η), although there was no proportionality to the solvent fluidity, η^?1. The morphology, which was in the scale of micrometres (as revealed by scanning electron microscopy), played a minor role in the shrinking rates of both types of gels. The excess swelling and the faster solvent response of macroporous gels were ascribed to the store and draining capacity of macropores at the millimetre scale. Copyright © 2005 Society of Chemical Industry     

Water‐soluble copolymers. I. Biodegradability and functionality of poly[(sodium acrylate)‐co‐(4‐vinylpyridine)]

As a biodegradable functional polymer, poly[(sodium acrylate)‐co‐(4‐vinylpyridine)] [P(SA‐co‐4VP)] containing a small amounts of 4‐vinylpyridine groups were prepared and their biodegradability, dispersity, and complex performance were analyzed. The polymers can be useful as detergent builders and dispersants. It was found that the biodegradation of P(SA‐co‐4VP) was more conspicuous when content of the 4‐vinylpyridine in the copolymer was larger. This indicates that the 4‐vinylpyridine, which acts as biodegradable segments, should be incorporated into the polymer main chain in such a manner that they are digested by activated sludge. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1953–1957, 1999     

Crosslinking of poly[(3‐hydroxybutyrate)‐co‐(3‐hydroxyvalerate)] using dicumyl peroxide as initiator

In order to modify poly [(3‐hydroxybutyrate)‐co‐(3‐hydroxyvalerate)] (PHBV), the crosslinking of this copolymer was carried out at 160 °C using dicumyl peroxide (DCP) as the initiator. The torque of the PHBV melt showed an abrupt upturn when DCP was added. Appropriate values for the gel fraction and crosslink density were obtained when the DCP content was up to 1 wt% of the PHBV. According to the NMR spectroscopic data, the location of the free radical reaction was determined to be at the tertiary carbons in the PHBV chains. The melting point, crystallization temperature and crystallinity of PHBV decreased significantly with increasing DCP content. The effect of crosslinking on the melt viscosity of PHBV was confirmed as being positive. Moreover, the mechanical properties of PHBV were improved by curing with DCP. When 1 wt% DCP was used, the ultimate elongation of PHBV increased from 4 to 11 %. A preliminary biodegradation study confirmed the total biodegradability of crosslinked PHBV. Copyright © 2004 Society of Chemical Industry     

Swelling kinetics of poly(N‐vinylimidazole‐co‐sodium styrenesulfonate) hydrogels

Hydrogels of N‐vinylimidazole and sodium styrenesulfonate were synthesized by radical crosslinking copolymerization. Transient swelling measurements in water, at room temperature, reveal an unusual behavior. For some gel compositions, the swelling time dependency is about a δ function: dry hydrogel pellets swell up readily to reach a high degree of swelling and, spontaneously, they deswell to collapse. Such peculiarity was interpreted in terms of several competing events in the swelling mechanism: water diffusion toward the gel, chain disentanglement, sodium–proton interchange through the gel–external bath boundary, approaching of chains to allow interaction of sulfonate groups with neighboring protonated imidazole moieties and diffusion of water outside the gel. The results of cyclic swelling–deswelling following abrupt changes of composition in the external bath, from water to sodium hydroxide solution, support that mechanism. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 191–200, 2002     

Effects of plasma treatment on biocompatibility of poly[(L‐lactide)‐co‐(ϵ‐caprolactone)] and poly[(L‐lactide)‐co‐glycolide] electrospun nanofibrous membranes

Poly[(l ‐lactide)‐co ‐(? ‐caprolactone)] (PLCL) and poly[(l ‐lactide)‐co ‐glycolide] (PLGA) copolymers are widely used in neural guide tissue regeneration. In this research, the surface modification of their hydrophilicity was achieved using plasma treatment. Attachment and proliferation of olfactory ensheathing cells on treated electrospun membranes increased by 26 and 32%, respectively, compared to the untreated PLCL and PLGA counterparts. Cells cultivated on both the PLCL and PLGA membranes showed high viability (>95%) and healthy morphologies with no evidence of cytotoxic effects. Cells grown on treated electrospun fibres displayed significant increases in mitochondrial activity and reductions in membrane leakage when compared to untreated samples. The results suggested that plasma treatment of the surface of the polymers enhanced both cell viability and growth without incurring any cytotoxic effects. © 2017 Society of Chemical Industry     

Specific interactions in poly(styrene‐co‐2‐hydroxyethyl acrylate)/poly(styrene‐co‐N,N‐dimethylacrylamide) systems

Amphiphilic copolymers of poly(styrene‐co‐2‐hydroxyethyl acrylate) (SHEA) and poly(styrene‐co‐N, N‐dimethylacrylamide) (SAD) of different compositions were prepared by free radical copolymerization and characterized by different techniques. Depending on the nature of the solvent and the densities of interacting species incorporated within the polystyrene matrices, novel materials as blends or interpolymer complexes with properties different from those of their constituents were elaborated when these copolymers are mixed together. The specific interpolymer interactions of hydrogen bonding type and the phase behavior of the elaborated materials were investigated by differential scanning calorimetry (DSC) and Fourier transform infra red spectroscopy (FTIR). The specific interactions of hydrogen bonding type that occurred within the SHEA and within their blends with the SAD were evidenced by FTIR qualitatively by the appearance of a new band at 1626 cm^?1 and quantitatively using appropriate spectral curve fitting in the carbonyl and amide regions. The variation of the glass transition temperature with the blend composition behaved differently with the densities of interacting species. The thermal degradation behavior of the materials was studied by thermogravimetry. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and in vitro degradation properties of poly[(tetramethylene carbonate)‐co‐(sebacic anhydride)]

A novel poly[(tetramethylene carbonate)‐co‐(sebacic anhydride)] (PTCSA) was synthesized by the melt polycondensation reaction of sebacic acid (SA) and the dicarboxylic acid which derived from oligo(tetramethylene carbonate) diol via the corresponding mixed anhydrides. The copolymer structure was confirmed by means of FTIR and [¹H] NMR spectra. DSC analysis showed PTCSA was semicrystalline polymer which had low T_g (<?30 °C). The measurements of contact angles indicated that the hydrophobicity of PTCSA increased as the content of carbonate segments increased. In vitro degradation of PTCSA was performed in lipase‐free and lipase‐containing phosphate‐buffer saline (0.1 M, pH 7.4) at 37 °C. It was found that the degradation rate of PTCSA increased with the amount of SA. After 7 days of degradation in lipase‐free phosphate‐buffer saline, the weight loss of PTCSA was 74, 49 and 22% for 80, 58 and 32 mol% SA contained samples, respectively. The weight loss of PTCSA increased rapidly in the first week, then slowed down but could be greatly enhanced by lipase. After 3 weeks of degradation with or without lipase, the weight loss of PTCSA was 66 and 52% for 58 mol% SA‐containing samples, respectively. The size of the samples was gradually reduced and the surface became coarse. It was also found that the molecular weights of the outer layer were lower than those of the inner layer of the samples after degradation. The results suggested that PTCSA was some kind of biodegradation and surface‐erosion material. © 2001 Society of Chemical Industry     

Synthesis and characteristics of a novel aliphatic polycarbonate,poly[(propylene oxide)‐co‐(carbon dioxide)‐co‐(γ‐butyrolactone)]

A novel aliphatic polycarbonate, poly[(propylene oxide)‐co‐(carbon dioxide)‐co‐(γ‐butyrolactone)] [P(PO? CO₂? GBL)], was synthesized by the copolymerization of carbon dioxide, propylene oxide (PO) and γ‐butyrolactone (GBL). The resulting copolymers were determined by FTIR and NMR spectral analysis with viscosity‐average molecular weights (M_v) from 50 000 to 120 000 g mol^?1. According to elemental analysis, the calculated data of elemental contents in P(PO? CO₂? GBL)44 were close to the found data. The result showed that GBL was inserted into the backbone of poly[(propylene oxide)‐co‐(carbon dioxide)] successfully. GBL offered an ester structural unit that gave the copolymer better degradability. The correlations between reaction conditions and properties were studied. When GBL content increased, the M_v and the glass transition temperature (T_g) of the copolymers improved relative to an identical copolymer without GBL. Prolonging the reaction time of the copolymerization resulted in increases in M_v and T_g. P(PO? CO₂? GBL) exhibited a high T_g above 40 °C. The rate of backbone degradation increased with increasing GBL content. Copyright © 2005 Society of Chemical Industry     

Interpolymer‐specific interactions and miscibility in poly(styrene‐co‐acrylic acid)/poly(styrene‐co‐N,N‐dimethylacrylamide) blends

The miscibility or complexation of poly(styrene‐co‐acrylic acid) containing 27 mol % of acrylic acid (SAA‐27) and poly(styrene‐co‐N,N‐dimethylacrylamide) containing 17 or 32 mol % of N,N‐dimethylacrylamide (SAD‐17, SAD‐32) or poly(N,N‐dimethylacrylamide) (PDMA) were investigated by different techniques. The differential scanning calorimetry (DSC) analysis showed that a single glass‐transition temperature was observed for all the mixtures prepared from tetrahydrofuran (THF) or butan‐2‐one. This is an evidence of their miscibility or complexation over the entire composition range. As the content of the basic constituent increases as within SAA‐27/SAD‐32 and SAA‐27/PDMA, higher number of specific interpolymer interactins occurred and led to the formation of interpolymer complexes in butan‐2‐one. The qualitative Fourier transform infrared (FTIR) spectroscopy study carried out for SAA‐27/SAD‐17 blends revealed that hydrogen bonding occurred between the hydroxyl groups of SAA‐27 and the carbonyl amide of SAD‐17. Quantitative analysis carried out in the 160–210°C temperature range for the SAA‐27 copolymer and its blends of different ratios using the Painter–Coleman association model led to the estimation of the equilibrium constants K₂, K_A and the enthalpies of hydrogen bond formation. These blends are miscible even at 180°C as confirmed from the negative values of the total free energy of mixing ΔG_M over the entire blend composition. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1011–1024, 2007     

Synthesis and network parameters of hydrophobic poly(N‐[3‐(dimethylaminopropyl)]methacrylamide‐co‐lauryl acrylate) hydrogels

Hydrophobic poly(N‐[3‐(dimethylaminopropyl)]methacrylamide‐co‐lauryl acrylate) [P(DMAPMA‐co‐LA)] hydrogels with different LA content were synthesized by free‐radical crosslinking copolymerization of corresponding monomers in water by using N,N‐methylenebis(acrylamide) as the crosslinker, ammonium persulfate as the initiator, and N,N,N′,N′‐tetramethylethylenediamine as the activator. The swelling equilibrium of the hydrogels was investigated as a function of temperature and hydrophobic comonomer content in pure water. An interesting feature of the swelling behavior of the P(DMAPMA‐co‐LA) hydrogels with low LA content was the reshrinking phase transition where the hydrogels swell once and collapse as temperature was varied in the range of 30–40°C. The average molecular mass between crosslinks (M?_c) and polymer–solvent interaction parameter (χ) of the hydrogels were calculated from equilibrium swelling values. The enthalpy (ΔH) and entropy (ΔS) changes appearing in the χ parameter for the hydrogels were determined by using the Flory–Rehner theory based on the phantom network model of swelling equilibrium. The positive values for ΔH and ΔS indicated that the hydrogels had a positive temperature‐sensitive property in water, that is, swelling at a higher temperature and shrinking at a lower temperature. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4159–4166, 2006     

Simultaneous lower and upper critical solution temperature‐type co‐nonsolvency behaviour exhibited in water–dioxane mixtures by linear copolymers and hydrogels containing N‐isopropylacrylamide and N,N‐dimethylacrylamide

The co‐nonsolvency behaviour in water–dioxane mixtures of linear copolymers and hydrogels consisting of N‐isopropylacrylamide (NIPAM) and N,N‐dimethylacrylamide (DMAM) was studied as a function of solvent composition and temperature. The composition of the copolymers, P(NIPAM‐co‐DMAMx), in DMAM units, x, varies from x = 0 up to x = 100%. It is shown that the copolymers combine the lower critical solution temperature (LCST)‐type co‐nonsolvency behaviour of poly‐NIPAM with the upper critical solution temperature (UCST)‐type co‐nonsolvency behaviour of poly‐DMAM. Depending on x, both the LCST‐ and UCST‐type co‐nonsolvency behaviour may be simultaneously observed in water‐rich and dioxane‐rich solvent mixtures, respectively. Due to this complex phase separation behaviour, the variation of the reduced viscosity of the linear copolymers, as well as the swelling–deswelling behaviour of the respective hydrogels, are shown to be temperature‐ and solvent‐sensitive. Copyright © 2006 Society of Chemical Industry     

Nanocomposites of poly[(butylene succinate)‐co‐(butylene adipate)] (PBSA) and twice‐functionalized organoclay

A new method is described to prepare composites of poly[(butylene succinate)‐co‐(butylene adipate)] (PBSA) with an organophilic clay having a particular functional group, namely twice‐functionalized organoclay (TFC). TFCs were produced by treating Cloisite 25A^® with (glycidyloxypropyl)trimethoxy silane (GPS) or (methacryloyloxypropyl)trimethoxy silane (MPS). Reaction of the silane compound with the organoclay surface was monitored by Fourier‐transform infrared spectroscopy (FTIR). PBSA composites with the three different clays were prepared successfully via melt mixing. The d spacing and the morphology of the composites were monitored by X‐ray diffraction and by transmission electron microscopy. The linear storage modulus of the composites in the melt state increased significantly as a result of incorporation of TFC. Tensile modulus and strength at break of PBSA/TFC–GPS and those of PBSA/TFC–MPS were far superior to those of PBSA/C25A. Copyright © 2005 Society of Chemical Industry     

Metal complexation studies of amylopectin‐graft‐poly[(N,N‐dimethylacrylamide)‐co‐(acrylic acid)]: a biodegradable synthetic graft copolymer

Synthesis of amylopectin‐graft‐poly[(N,N‐dimethylacrylamide)‐co‐(acrylic acid)] was carried out using solution polymerization technique with potassium persulfate as the initiator. The graft copolymer was characterized by measuring molecular weight using size exclusion chromatography, thermal analysis and Fourier transform infrared (FTIR) spectroscopy. The synthetic graft copolymer was used for the removal of some potentially toxic metal ions, Cu(II), Zn(II) and Ni(II), from their aqueous solutions. Various operating parameters like the amount of adsorbent, solution pH, contact time and temperature were studied. The adsorption data were well described by the pseudo‐second‐order and Langmuir isotherm models. Metal complexation studies were carried out experimentally using cyclic voltammetry and UV‐visible and FTIR spectroscopies. The metal complex structure was also studied theoretically using density functional theory with the Gaussian 09 program and the geometry of the complex structure was optimized. The metal complexation ability of the graft polymer was in the order Cu(II) > Ni(II) > Zn(II). Calculation of the various thermodynamic parameters was also done. The negative value of free energy change indicates the spontaneous nature of the adsorption. © 2015 Society of Chemical Industry