Effects of Enteromorpha prolifera sulfated polysaccharide and aluminium ion addition on the multifunctional property of conductive hydrogel for wearable strain sensing.

Although introducing Enteromorpha prolifera sulfated polysaccharide (SPEP) enhances the mechanical properties of hydrogels significantly, little is known about the effects of polysaccharide and ion addition on morphological and physicochemical properties of conductive hydrogel. Therefore, the Poly (acrylic acid)/SPEP/Al (PAA/SPEP/Al) hydrogels with different SPEP and Al addition were synthesized by simple one-pot method. The porosity, tensile strength, and swelling ration increased, while compressive strength, elongation at break, self-healing, self-adhesion properties increased first and then decreased as SPEP addition increased from 0 % to 3.80 %. The Al addition increased from 0.08 % to 0.30 %, both tensile and compressive strength increased first and then decreased, while elongation at break kept increasing. Unexpectedly, both increasing SPEP and Al addition reduced the electrical conductivity, while SPEP increased the gauge factor of hydrogel. The hydrogel exhibited optimal comprehensive properties when SPEP and Al addition were 2.31 % and 0.24 %, respectively. The PAA/SPEP/Al hydrogel showed high tensile strength (107.60 kPa), elongation at break (2426.67 %), strain self-healing rate (81.87 %), adhesion strength (21.61 kPa), and conductivity (3.60 S/m). Overall, the properties of PAA/SPEP/Al hydrogels can be regulated through tailoring SPEP and Al addition, which can be used as on-demand strategy to improve the performance of PAA/SPEP/Al hydrogels for each application.