Electrically induced swelling and methylene blue release behaviour of poly (N-isopropylacrylamide-co-acrylamido-2-methylpropyl sulphonic acid) hydrogels

Abstract

Hydrogels composed of poly (ethylene glycol) (PEG)/poly (N-isopropylacrylamide-co-acrylamido-2-methylpropyl sulphonic acid) exhibited electro-responsive behaviour. The swelling properties of hydrogels were influenced by the content of negatively charged ionic groups inside the network structure, cross-linking density, electric field intensity and electrolyte solution. The swelling ratio (SR) increased from 92.4 to 188.08, and normalized swelling ratio (NSR) increased from 2.88 to 3.62 depending on 2-acrylamido-2-methylpropane sulphonic acid (AMPS) concentration under electric field intensity 429 V/m. The swelling process of hydrogels in deionized water followed non-Fickian diffusion in the absence of electric field and Super Case II transport model in presence of electric field. The methylene blue (MB) was used as a model drug, and the influence of various factors like loading percent of MB, AMPS concentration in hydrogels, pH of the release medium and applied electric field was investigated on the release profiles of the MB. The release study showed that the interaction between hydrogels and MB, pH of the medium and electric field are the parameters that affect the releasing behaviour of methylene blue. The partition coefficient (K d ) of MB in hydrogels increased with increasing AMPS content in the hydrogels. The application of external electric field has increased the time response of swell and release of methylene blue through hydrogels.

Lignin-based hydrogels with “super-swelling” capacities for dye removal

“…The obtained percentage of MB released from the hydrogels ranged from 0.06 to 0.35 %. These results were lower than those obtained with other synthetic hydrogels described in the literature (ranged from 0.44 to 35.22 %) [51]. These results could be explained by the entrapment of the MB molecules within the network structure of the hydrogels and by the strong binding interactions between the MB molecules due to the negative charge of the hydrogels.…”

“…Synthetic hydrogel composed of poly (ethylene glycol) (PEG)/poly (N-isopropylacrylamide-co-acrylamido-2-methylpropyl sulphonic acid) presented a water intake values around 60 g/g. Moreover, the same hydrogel was able to absorb about 200 g/g when placed within an electric field [51].…”

Alginate Bioconjugate and Graphene Oxide in Multifunctional Hydrogels for Versatile Biomedical Applications

“…As reported in the literature, this effect can be explained as the result of two main phenomena, i.e., ionization of the COOH functionalities and generation of an osmotic pressure between the inner and outer portions of the hydrogel network, due to the re-arrangement of mobile ions moving to the opposite electrodes [ 54 ].…”

Dual Stimuli Responsive Gelatin‐CNT Hybrid Films as a Versatile Tool for the Delivery of Anionic Drugs

“…At the same time, the ions in the swelling medium also migrate toward their respective counter electrode moving through hydrogel structure. As a result, the osmotic stress is created along the network resulting in a hydrogel deformation . This effect is obviously not evident in H B samples due to the low conductivity properties of pure Gel, while becoming clearly evident when MWNT_COOH are inserted in the polymer network since they enhance the polarizability of the whole system …”