Electrostatic Adhesion Clutch with Superhigh Force Density Achieved by MXene-Poly(Vinylidene Fluoride-Trifluoroethylene-Chlorotrifluoroethylene) Composites.

Electrostatic adhesion (EA) clutches are widely applied in robots, wearable devices, and virtual reality, due to their compliance, lightweight, ultrathin profile, and low power consumption. Higher force density has been constantly perpetuated in the past decades since EA was initially proposed. In this study, by composing terpolymer poly(vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene) [P(VDF-TrFE-CTFE)] and two-dimensional Ti3C2Tx nanosheets (MXene), nanocomposite films with high dielectric constant (δr' > 2300) and low loss tangent are achieved. The force representative index δr'Ebd2 (the relative dielectric constant times the square of breakdown electric field) is enhanced by 5.91 times due to the charge accumulation at matrix-filler interfaces. Superhigh shear stress (85.61 N cm-2) is generated, 408% higher than the previous maximum value. One of the EA clutches fabricated in this study is only 160 µm thin and 0.4 g heavy. Owing to the low current (<1 µA), the power consumption is <60 mW/cm2. It can hold a 2.5 kg weight by only 0.32 cm2 area and support an adult (45 kg) (Clinical Trial Registration number: 20210090). With this technology, a dexterous robotic hand is displayed to grasp and release a ball, showing extensive applications of this technique.

Accelerating the oxidation of pork fat by illumination and fat oil for the production of Baijiu beverage.

BACKGROUND: Aged pork fat, deeply oxidized pork fat soaked in basic liquor for more than half a year, is an important material in producing Chi-aroma Baijiu (CAB). With the expansion of production scale of CAB, innovative strategies for efficient production of aged pork fat are in great demand. The purpose of this study is to accelerate the lipid oxidation of pork fat and improve the productivity of aged pork fat. RESULTS: Results showed that polyunsaturated fatty acids (PUFAs) were the main reactant; generation reactions of lipid peroxides and free fatty acids (FFAs) were two limiting steps during the preparation of aged pork fat. Processing under illumination could alleviate the first limiting step by increasing the peroxide value and p-anisidine value of pork fat to 16.22- and 28.48-fold higher than control samples and simultaneously the PUFAs were increased to 190.60 ± 0.19 g kg-1 . Soaking in basic liquor with deeply oxidized fat oil could alleviate the second limiting step by transferring FFAs from fat oil into pork fat. With more oxidized PUFAs, the acid value of the pork fat was 7.91-fold higher than that of the control. CONCLUSION: Illumination and deeply oxidized fat oil could alleviate the two rate-limiting steps of lipid oxidation and improve the productivity of aged pork fat significantly. The results are highly applicable in the CAB industry. © 2020 Society of Chemical Industry.