Preparation of polyvinyl alcohol formaldehyde-g-poly(2-(dimethylamino) ethyl methacrylate) macroporous hydrogels and their dual thermo/pH-responsive behavior and antibacterial performance

Herein, the dual thermo/pH-responsive hydrogels were successfully fabricated by grafting poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) segments onto polyvinyl alcohol formaldehyde (PVF) sponges. Due to the interconnected micron-sized pore structure and high porosity (similar to 85.0%), the PVF-g-PDMAEMA hydrogels can reach saturated water absorption within 60-180 min, of which 90% of water absorption capacity can be achieved within 20-60 min, showing a much faster water absorption rate than traditional PDMAEMA hydrogels without pores. Moreover, the hydrogels exhibit obvious pH-responsiveness and weak thermo-sensitivity through evaluating the absorption capacities in buffers or water with the alternation of pH value or temperature by a mass method. Besides, the hydrogels show excellent repeated absorption performance by detecting absorption capacities in the absorption-extrusion tests for 10 cycles. In addition, the main water loss of hydrogels occurs within 360 min when they are transferred from pH 2 buffer to pH 12 buffer. The absorption capacity of hydrogels shows a significant fluctuation when the pH value of buffer fluctuates between 2 and 12, indicating an outstanding swelling-deswelling responsive reversibility. Furthermore, the hydrogels display excellent antibacterial activities against gram-negative (E. coli) and gram-positive (S. aureus) bacteria and may be applied in multifunctional field as stimuli-responsive and antibacterial materials.

Automated summary

The study successfully fabricated dual thermo/pH-responsive hydrogels with high water absorption rate and repeated absorption performance, showing significant pH responsiveness and antibacterial activities.