The industrial demand for novel and smart materials as well as the urge for basic understanding has led to a notable improvement in the area of polymer science. Recently, significant consideration has been given to the modifications of biodegradable hydrogels based on natural polymers with conducting polymers (CPs), because this extends a straightforward process to couple the better features of CPs with the highly cross-linked hydrogels. The final hydrogels have been developed to change mainly electrical and structural properties to a larger degree. Herein, we present a comprehensive survey of the existing and current literature on conducting hydrogels based on natural polymers. This chapter also highlights ample of methods used to synthesize conducting hydrogel, properties, and characterization techniques. Conducting hydrogels have been used in the removal of dyes from wastewater, drug delivery, fuel cells, supercapacitors, dye-sensitized solar cells, rechargeable lithium batteries, etc. All these justify the rising interest in both academia and industrial development. In this analysis, an overview of potential applications of these conducting hydrogels and current challenges in the field are discussed; some new and futuristic advances in this captivating area are also provided.

Conductive superabsorbent hydrogels based on gum ghatti (Gg)/methacrylic acid (MAA)/aniline (ANI) were synthesized by gamma radiations initiated by two-step aqueous polymerization. A cross-linking agent N,N'-methylene-bis-acrylamide was used in the polymerization process, and MAA was graft-copolymerized onto Gg by gamma-rays. Influence of preparative conditions (absorbed dose, monomers, solvent, and cross-linker concentrations) on the swelling behavior of cross-linked polymer systems has been investigated. Synthesized superabsorbent hydrogels were characterized using thermogravimetric analysis and swelling studies. In biodegradation study of synthesized hydrogels by composting soil method, Gg-cl-poly(MAA-ipn-ANI) showed better degradation efficiency in comparison to Gg-cl-poly(MAA). Synthesized hydrogels were loaded with amoxicillin trihydrate as a model drug to investigate the release behavior of hydrogels at different pH media. Kinetics studies revealed that synthesized hydrogels exhibit a Fickian diffusion behavior at pH 2.4 and 7.2. However, at pH 9.2, a non-Fickian diffusion behavior was observed which make them very suitable for colon-specific drug delivery applications.

Poly(acrylamide-aniline)-grafted gum ghatti [Gg-cl-poly(AAm)] conducting hydrogel was prepared via Co-60, gamma-irradiation using N, N'-methylene-bis-acrylamide as a cross linker. The effects of the reaction conditions (viz, gamma dose, monomer, solvent and cross linker concentration) were investigated on the degree of swelling of Gg-cl-poly(AAm). Results showed that optimum reaction conditions for maximum percentage swelling were 10 ml of solvent, 1.08 mol/L of monomer concentration, 0.324 x 10(-1) mol L-1 of crosslinker concentration and 1.5 kGy of total dose. The semi-interpenetrating network (Semi-IPN) was converted into an IPN through the impregnation of poly(aniline) chains followed by doping with HCI. The influence of dopant concentration on the conductivity of synthesized hydrogel was investigated. Different physical properties of the synthesized hydrogel were also studied. The candidate polymers were characterized using different techniques such as X-ray diffraction and thermogravemetric analysis techniques. The mechanism of graft copolymerization via Co-60 irradiation was discussed. Biodegradation studies of the synthesized hydrogels were carried out using a soil burial test. IPN showed better degradation efficiency than semi-IPN. Weight loss of semi-IPN and IPN was 68% and 78%, respectively, in 60 days. Different degradation stages were studied using FTIR and SEM techniques. (C) 2014 Elsevier Ltd. All rights reserved.

In this work, we have synthesized poly(acrylamide-aniline)-grafted gum ghatti based crosslinked conducting hydrogel via a two-step synthesis method. The first step involved the microwave assisted synthesis of a semi-interpenetrating polymer network (semi-IPN) based on acrylamide and gum ghatti using N, N'-methylene-bis-acrylamide and ammonium persulfate as a crosslinker-initiator system. The semi-IPN has been observed to exhibit as much as 2183% swelling in aqueous solution. The effect of several variables such as time, solvent, pH, microwave power, crosslinker amount, aniline concentration, initiator concentration and monomer concentration on the swelling capacity was explored. In the final step, polyaniline was entrapped within a semi-IPN (optimized reaction condition) followed by doping with hydrochloric acid, which leads to the formation of conducting IPN. The synthesized hydrogels, as monitored by the swelling behaviour were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy and thermogravimetric analysis. Finally, the synthesized crosslinked networks have been used in malachite green (MG) adsorption. The result indicates that IPN of poly(acrylamide-aniline)-grafted gum ghatti are potential candidates for dye removal from water.

Gum ghatti-based cross-linked hydrogels have been studied for their water absorption, flocculation and biodegradation properties. To date, a lot of research has been focused on gum ghatti-based cross-linked hydrogels; however, the synthesis and characterization of gum ghatti-based conductive biomaterials are relatively less explored. Moreover, the biodegradation and moisture retention studies have not been reported for conductive hydrogels. A gum ghatti-based electrically conductive hydrogel was prepared through a two-step aqueous polymerization. Biodegradation studies of the synthesized hydrogels were conducted using a soil burial test. Interpenetrating network structures showed better degradation efficiency than semi-IPN. The weight loss of semi-IPN and IPN was 66% and 86.6%, respectively, in 60 days. Different stages of degradation were studied using FTIR and SEM techniques. Furthermore, application of hydrogels to improve the water retention properties of different soils was studied for agricultural purposes, and it was found that the IPN hydrogel can improve the moisture retention capacity of soil for cultivation.

Gum ghatti-based cross-linked hydrogels have been studied for their water absorption, flocculation and biodegradation properties. To date, a lot of research has been focused on gum ghatti-based cross-linked hydrogels; however, the synthesis and characterization of gum ghatti-based conductive biomaterials are relatively less explored. Moreover, the biodegradation and moisture retention studies have not been reported for conductive hydrogels. A gum ghatti-based electrically conductive hydrogel was prepared through a two-step aqueous polymerization. Biodegradation studies of the synthesized hydrogels were conducted using a soil burial test. Interpenetrating network structures showed better degradation efficiency than semi-IPN. The weight loss of semi-IPN and IPN was 66% and 86.6%, respectively, in 60 days. Different stages of degradation were studied using FTIR and SEM techniques. Furthermore, application of hydrogels to improve the water retention properties of different soils was studied for agricultural purposes, and it was found that the IPN hydrogel can improve the moisture retention capacity of soil for cultivation.

Abstract In this work, biodegradable hydrogel composite gum ghatti-co-poly(acrylic acid-aniline) (Gg-co-poly(AA-ANI) was prepared through graft copolymerization of ANI onto Gg-co-poly(AA) chains, in the presence of N,N’-methylene-bis-acrylamide (MBA) and ammonium persulphate (APS) as a crosslinker-initiator system in an aqueous solution. The matrix Gg-co-poly(AA) was synthesized by polymerizing AA onto Gg backbone using MBA and APS as a crosslinker-initiator system. The characterization of the crosslinked hydrogels has been carried out by Time of flight secondary ion mass spectroscopy, Fourier transform infrared, X-ray diffraction and thermogravimetric analysis. These spectroscopic studies confirmed the successful graft polymerization. The biodegradation of the crosslinked hydrogels was analysed using the composting soil method for two months. The initial and final weight of the crosslinked hydrogels were compared as well as the percentage degradation was calculated. The capability of the synthesized hydrogels to be employed as a colon-specific drug delivery vehicle was executed at various pH media using amoxicillin trihydrate as a model drug. The crosslinked hydrogel with the maximum percentage swelling was observed to show best drug absorption. Preliminary kinetic studied were conducted to get an estimated view of the release mechanism.

In this work, biodegradable hydrogel composite gum ghatti-co-poly(acrylic acid-aniline) (Gg-co-poly(AA-ANI) was prepared through graft copolymerization of ANI onto Gg-co-poly(AA) chains, in the presence of N,N'-methylene-bis-acrylamide (MBA) and ammonium persulphate (APS) as a crosslinker-initiator system in an aqueous solution. The matrix Gg-co-poly(AA) was synthesized by polymerizing AA onto Gg backbone using MBA and APS as a crosslinker-initiator system. The characterization of the crosslinked hydrogels has been carried out by Time of flight secondary ion mass spectroscopy, Fourier transform infrared, X-ray diffraction and thermogravimetric analysis. These spectroscopic studies confirmed the successful graft polymerization. The biodegradation of the crosslinked hydrogels was analysed using the composting soil method for two months. The initial and final weight of the cross linked hydrogels were compared as well as the percentage degradation was calculated. The capability of the synthesized hydrogels to be employed as a colon-specific drug delivery vehicle was executed at various pH media using amoxicillin trihydrate as a model drug. The crosslinked hydrogel with the maximum percentage swelling was observed to show best drug absorption. Preliminary kinetic studied were conducted to get an estimated view of the release mechanism. (C) 2015 Elsevier Ltd. All rights reserved.

A systematic comparative study was carried out for the induced changes in the chemical, structural, morphological and thermal properties of poly(methacrylic acid) grafted gum ghatti i.e. [Gg-cl-poly (MAA)] material by irradiation of 120 MeV Nig+ and Aug+ ions at various fluences ranging from 3 x 1011 to 3 x 1012 ions/cm2. The degradation of the material was observed after ion irradiation. A significant loss of crystallinity and change in the crystallite size was observed in irradiated samples of Gg-cl-poly(MAA). The changes in chemical properties and surface morphology were observed by Fourier transform infrared spectroscopy and scanning electron microscopy respectively. The magnitude of the effect of the irradiation was observed to be greater in the case of Aug ions irradiation than those of Nig+ ions irradiation due to the high electronic energy loss of the Aug' ions in the grafted samples. (C) 2013 Elsevier Ltd. All rights reserved.

The objective of the present investigation was to develop colon-specific drug delivery systems for amoxicillin trihydrate and paracetamol using Gum ghatti (Gg) based cross-linked hydrogels. An interpenetrating network (IPN) of electrically active hydrogel based on Gg, poly(acrylic acid) (AA) and polyaniline was synthesized by a two-step aqueous polymerization. The radical copolymerization of Gg and AA was done using N, N'-methylene-bis-acrylamide (MBA) and ammonium persulphate (APS) as a crosslinker-initiator system. Optimum operating conditions for maximizing the percentage swelling were solvent (ml) =3D 10, AA (mol L-1) =3D 0.291 x 10(-3), APS (mol L-1) =3D 0.219 x 10(-1), MBA (mol L-1) =3D 0.324 x 10(-1), reaction time (min) =3D 180, temperature (1C) =3D 60 and pH =3D 7.0. The synthesized semi-IPN matrix was further grafted with aniline through oxidative-radical copolymerization using APS in acidic media. The resultant cross-linked hydrogels were characterized using X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy, ToF-SIMS and electrical conductivity. The maximum conductivity was found to be 2.5 x 10(-6) S cm(-1) at 1.5 N HCl concentration. The synthesized hydrogels were loaded with amoxicillin trihydrate and paracetamol as model drugs to investigate the release behaviour. Amoxicillin trihydrate follows the surface phenomena and weak bonding interaction whereas paracetamol exhibited chemical interaction with the hydrogel matrices. The release rate of both the drugs through the synthesized hydrogel matrices was found to show Fickian behaviour at each pH. The hydrogel networks showed lower release in acidic and neutral media than in basic media, making them particularly suitable carriers for colon-specific drug delivery.