4.7 Characterization
The hydrogels’ mechanical properties
were measured using a UTM2203 universal testing machine (Technology
Stock Co., Ltd., Shenzhen, China) at a stretching rate of 50 mm
min−1. A CEL-SSOO xenon lamp (Au-light Co., Ltd.,
Beijing, China), simulating solar irradiation, served as the light
source. Voltage changes were recorded with a Keithley 6514 system
electrometer (Keithley Co., Ltd., Johnston City, Ohio, USA). The
electrical conductivity of the hydrogels was measured using a Quantum
Design PPMS-9 measurement system (Ceshigo, Chengdu, China). Surface
temperature of the hydrogels was measured with a UT325 thermometer
(Alibaba). UV-Vis absorption spectra were recorded from 200 to 800 nm
using a TU-1901 UV-Vis double-beam spectrophotometer (Persee General
Instrument Co., Ltd., Beijing, China).