2.2. Preparation of CG and CGZP Films

Half a gram of ZnO/PAL powders were added into 50 mL of deionized water, then magnetically stirred for 3 h followed by ultrasonic dispersion for 20 min. Glacial acetic acid (1%, v/v) and 0.015 g of GA powder (0.5 wt.% of the total mass of CS) were dissolved in 45.5 mL deionized water. Then, 0 wt.% (0 mL), 0.25 wt.% (0.75 mL), 0.5 wt.% (1.5 mL), 1.0 wt.% (3.0 mL), 2.5 wt.% (7.5 mL), 5.0 wt.% (15.0 mL) of ZnO/PAL suspension, 3 g of CS and the corresponding volume of deionized water were added in the GA solution. The mixed solution was stirred at ambient temperature for 6 h. Thereafter, 40 wt.% GL aqueous solution was added into the mixture for another 1 h to obtain homogeneous solutions. The film-forming solutions were spread out to the sterile Petri dishes and air-dried at room temperature, and the finally formed films were coded as CG, CGZP−0.25%, CGZP−0.5%, CGZP−1.0%, CGZP−2.5%, CGZP−5.0%, respectively.