Hydrogel is swelling of 3D crosslinked polymeric network when large amount of solvent added. Most of the solvent use usually is water. Hydrogel is “smart material” due to its responses on environment such as temperature, pH, and ionic strength with extent of swelling (or de-swelling) properties. The unique property of the multi-responsive polymer hydrogels is that they can exhibit an special “on/off” mechanism for the controlled release or sensing of target molecules in response to small changes in its environmental conditions. Cross-linked polymeric net- work (colloidal particles) in a suitable solvent that is able to swell with large amounts of solvent is called polymer gel. Polymeric materials with multi-responsive behaviour toward various stimuli have broad applications in many fields, such as controlled drug delivery, chemical separation, sensors and micro reactors. While the polymer hydrogel consisting of magnetic, semi-conductor and metal nanoparticles are known as hybrid hydrogels. These inorganic nanoparticles in hydrogels are of great importance due to their potential applications in drug delivery, bio-sensing, photolithography, antibacterial activity, photonics, electronics, and catalysis and hydrogen storage.
Chitosan is insoluble in neutral and basic environment but in acidic environment, protonation of the amino groups leads to an increase its solubility. The solubility of chitosan is depending on the degree of deactylation, pH and on the protonation of free amino. Large quantities of the amino group on its chain increase the ability of the chitosan to produce dual-stimuli-responsive polymeric gel to be used as delivery vehicles that respond to localized condition of pH and temperature in human body. Synthesize modification and characterization with some multiple responsive chitosan hydrogel is important for variety potential applications for this materials.
Apparatus set up for the preparation of hydrogel
Example synthesis of Chitosan-p(MAA-co-NIPAM) hydrogel