Simple, convenient, low‐cost, and solventless greener way to pH‐responsive polymeric hydrogels: Synthesis and characterization

Abstract

Utilization of hydrogels in a simple, low-cost, solventless. and greener approach toward the pH-responsive hydrogels which comprise of citric acid (CA) with varying glycol unit viz., ethylene glycol (EG), diethylene glycol (DEG), and triethylene glycol (TEG) were prepared along with methacrylic acid (MAA). The formations of pre-polymer and hydrogels were confirmed using 13 C-NMR and FT-IR spectral techniques. Thermal studies (TGA, DTA, and DSC) and morphology (SEM) of various hydrogels have been investigated. Swelling studies of hydrogels at different pH ranging from 4.0 to 10.0 have also been performed. The results of swelling studies imply that the percentage of swelling is comparatively higher at neutral pH than acidic and alkaline pH. The reciprocal relationship was identified among thermal stability and swelling behavior of hydrogels while increasing the chain length from EG to TEG.

Separation free C3N4/SiO2 hybrid hydrogels as high active photocatalysts for TOC removal

“…The 3D hydrogels are one of the most widely used materials for water purification due to their low cost and outstanding performance for water pollutants adsorption and concentration [18][19][20][21]. The 3D network structure of hydrogels can not only provide convenient mass transfer channels, but also prevent the materials from dispersing or aggregation in water, greatly simplified the separation of the materials from water [22][23][24][25]. However, the pollution problem cannot be solved completely by hydrogels for the organic pollutants just can be concentrated and separated from water rather than degraded to non-polluting molecules.…”

Investigation of citric acid–glycerol based pH-sensitive biopolymeric hydrogels for dye removal applications: A green approach

“…The series of five different hydrogels (AC1G4, AC2G3, ACG, AC3G2 and AC4G1) showed equilibrium swelling for all samples exhibiting maxima at a higher pH than lower pH. It can be seen from the literature, the addition of CA found to have tuned the swelling equilibrium (Yang et al, 2004;Franklin and Guhanathan, 2014a, 2014b, 2015a, 2015b. The Seq % value of AC1G4 hydrogel at pH 4.0, 6.0, 7.4, 8.0 and 10.0 found to have 200.00%, 500.00%, 972.20%, 1225.00% and 1891.66%, respectively.…”

“…The synthesis of biopolymeric hydrogel was described in our earlier communications (Franklin and Guhanathan, 2014a, 2014b, 2015a, 2015b. Citric acid (0.025 mol -4.8 g) was taken in a round bottomed flask fitted with mechanical stirrer and nitrogen inlet.…”

“…Acrylic acid (AA) was used to establish pH sensitive biopolymeric hydrogels (Myung et al, 2007;Guo et al, 2007). Recently, our research group have synthesized a biocompatible hydrogels of citric acid which can exhibited pH-dependent swelling behavior (Franklin and Guhanathan 2014a, 2014b, 2015a, 2015b.…”

Antioxidant Properties of Indole-3-Acetic Acid based Biopolymeric Hydrogels

“…The signals were 63.95-68.78 ppm marked as a carbon atom of -CO-O-CH2-CH2-present in the polyester network [29]. The ester carbonyl carbon peaks were 170.17-173.70 ppm [30]. The signals between 39.462 and 40.420 ppm were indicated as DMSO [31].…”