Do polyacrylamide hydrogels have higher adhesion energy?

Specifically, at extremely low water content of ∼ 30%, polyacrylamide hydrogels exhibit one order of magnitude higher adhesion energy than that at relatively high water content. It is also found that with the decrease of water content, the maximum peeling force presents a similar trend to that of adhesion energy.

What is the adhesion behavior of polyacrylamide and polyacrylic acid hydrogels?

Adhesion behavior was completed in a few seconds at room temperature. Polyacrylamide (PAAm) and polyacrylic acid (PAAc) hydrophobic association hydrogels were synthetized via free radical polymerization, respectively. Also, the hydrophobic alkyl groups were introduced into PAAm and PAAc to enhance the mechanical properties of hydrogels.

What is the relationship between polyacrylamide hydrogel and substrate?

The surface chain density and bulk energy dissipation of the polyacrylamide hydrogel and the water content and effective contact area over the interface between the hydrogel and the substrate synergistically contribute to this relationship.

What is the force/width-displacement curve of polyacrylamide hydrogels?

The force/width-displacement curves of polyacrylamide hydrogels with water contents ranging from 29% to 90% are shown in Fig. S4, the curves of hydrogels with water content of 23%, 26%, and 95% are not shown since they are almost non-adhesive.

How much water is in polyacrylamide hydrogel?

Polyacrylamide hydrogels with 18 various water contents (23% − 95%) are prepared and then measured under 90-degree peeling tests. Experimental results show that as the water content changes, the adhesion energy-water content relation can be divided into four regions.

How thick is a polyacrylamide hydrogel slab?

The initial thickness of preformed polyacrylamide hydrogel slabs was 1.9 mm. With the change of water content, the thickness and side length of a hydrogel slab also changed accordingly (Fig. 2).