Hydrogel physical properties of the water contact angle and electrical conductivity. There is no significant differences between the samples.

Hydrogel	Water contact angle (degree)	Electrical conductivity (S m−1)
PVA	30.79 ± 3.40	0.0132 ± 0.0
PVA/Gr001	31.47 ± 0.30	0.0125 ± 0.00127
PVA/Gr005	21.64 ± 2.07	0.0125 ± 0.00127
PVA/GO	27.39 ± 2.96	0.0110 ± 0.0
PVA/Av	29.39 ± 4.43	0.0154 ± 0.00221
PVA/Gr001/Av	30.56 ± 2.29	0.0117 ± 0.00127
PVA/Gr005/Av	14.95 ± 1.70	0.0102 ± 0.00127
PVA/GO/Av	28.97 ± 3.97	0.0154 ± 0.00221