Hydrogels made from chitosan and silver nitrate

• Chitosan–silver hydrogels were made.
• Preparation of chitosan–silver sponges is shown.
• Preparation of chitosan–silver nano- and micro-hydrogels is shown.
• Preparation of antimicrobial cotton textile is presented.
• The products obtained act against Escherichia coli and Bacillus subtilis.

This work describes a gelation of chitosan solution with silver nitrate. Above the critical concentration of chitosan (c*), continuous hydrogels of chitosan–silver can be formed. At lower concentrations, the formation of nano- and micro-hydrogels is discussed. The sol–gel analysis was performed to characterise the hydrogels’ swelling properties. Moreover, the following were employed: (i) mechanical testing of hydrogels, (ii) inductively coupled plasma-optical emission spectroscopy (ICP-OES) for the measurement of silver concentration, (iii) scanning electron microscopy (SEM) to examine the morphology of products obtained, and (iv) dynamic light scattering (DLS) and UV–vis spectrophotometry to examine products formed at low concentration of chitosan (c < c*). Some hydrogels were used for modification of cotton fabric in order to give it antimicrobial properties. The products obtained acted against Escherichia coli and Bacillus subtilis apart from the chitosan used that showed no such activity.