Introduction: Wound hydrogel dressings are valued for maintaining a moist environment that promotes tissue regeneration. Incorporating antibacterial components may reduce infections and accelerate healing. This study evaluated the visual integrity of hydrogels by varying quaternary ammonium monomer and crosslinker content.

Methods: As monomers containing quaternary ammonium groups, 2-(methacryloyloxy)ethyl-2-hydroxyethylmethyloctylammonium bromide (QAHAMA-8) and 2-(methacryloyloxy)ethyl-2-decylhydroxyethylmethylammonium bromide (QAHAMA-10) were used in amounts ranging from 2.5 to 100 mol.%. As the crosslinker N,N′-methylenebisacrylamide (bis-AA) was used, and its content ranged from 0.5 to 5 mol.%. As the basic monomer acrylamide (AA) was used, and its content ranged from 0 to 97.5 mol.%, in respect to QAHAMA-10.

Results: Significant differences in sample integrity were observed. The mechanical integrity of the obtained hydrogels depended on both cross-link density and the content of quaternary ammonium monomer. At lower QAHAMA-8 and QAHAMA-10 contents, hydrogels with lower cross-linker amount, i.e., 0.5 and 1 mol.%, were integral. At higher QAHAMA-8 and QAHAMA-10 contents, hydrogels cross-linked with higher bis-AA contents were more integral. For example, for 0.5 mol.% bis-AA integral hydrogels were obtained for 2.5 mol.% to 10 mol.%, whereas for 50 and 100 mol.% of the quaternary ammonium monomer, integral hydrogels were obtained for 5 mol.% bis-AA. Overall, hydrogels of the higher visual quality were obtained for 1 mol.% of bis-AA and quaternary ammonium monomer for 5 mol.% to 30 mol.% (QAHAMA-8) and for 2.5 mol.% to 30 mol.% (QAHAMA-10).

Conclusions: The higher the bis-AA content, the greater the hydrogel brittleness. Only hydrogels cross-linked with 0.5 and 1 mol.% bis AA maintained their integrity over the entire concentration range of QAHAMA-8 and QAHAMA-10.