Constructing hydrogel networks for fabricating carboxymethyl konjac glucomannan/poly(vinyl alcohol) strain sensor

Exploring the application of carboxymethyl konjac glucomannan (CMK) in strain sensor is of great significance to expand the applications of konjac glucomannan (KGM) and its derivatives. Herein, CMK and poly(vinyl alcohol) (PVA) were used as substrates to prepare the hydrogels with dual characteristic networks. The primary network formed via the PVA crystallized zone was constructed via the freeze-thawing (F-T) treatments. By soaking with the Na + /Ca 2+ mixed solutions, the secondary network was constructed by coordinating Ca 2+ with carboxymethyl groups of CMK. Although the coordination of Ca 2+ -CMK degraded crystallizability of PVA, the salting-out effect of Na + enhanced the aggregation of CMK/PVA chains, densifying network structure. Accordingly, the overall mechanical properties and the anti-freezing performance of the hydrogel were improved remarkably. The as-obtained hydrogel could be well used as a soft strain sensor to detect human body motions and identify text signals. This work provides an attractive path of opening up new application scenario for CMK or other derivatives of KGM in the fields beyond food and biomedical applications.