Insights on the influence of functional side groups on the mechanical performance of Poly(2-oxazoline)/Poly(acrylate) double network hydrogels

Double network hydrogels (DNHs) are strong and tough materials that surpass the performance of conventional hydrogels, making them highly attractive for various applications in biomedicine, membrane technology, and energy storage. The number of suitable systems known so far is rather limited. We have recently introduced a poly(2-oxazoline) (POx)-based DNH combined with poly (acrylic acid) that has a superior compressive strength compared to common DNHs entirely composed of two poly(acrylate) networks. To further explore the potential of cross-linked POx as primary networks for DNHs, a series of different poly (acrylate)s was employed as secondary network and the resulting DNHs were investigated regarding their mechanical properties. • Nonionic poly(2-oxazoline) networks with different acrylates are synthesized for the first time. • Double network structure and hydrogen bonds are essential for high mechanical strength of the DNHs. • Side groups of poly(2-oxazoline) and poly acrylate network must be matching for high toughness and strength. • PMOx/PHEAm DNHs show the highest toughness if 10 wt% of AAm are added to the poly(acrylate) network. • Strength of hydrogen bonds within the secondary network have great impact on high compression strength of DNHs.