Both relaxor ferroelectric and antiferroelectric materials can individually demonstrate large electrocaloric effects (ECE). However, in order to further enhance the ECE it is crucial to find a material system, which can exhibit simultaneously both relaxor ferroelectric and antiferroelectric properties, or easily convert from one into another in terms of the compositional tailoring. Here we report on a system, in which the structure can readily change from antiferroelectric into relaxor ferroelectric and vice versa. To this end relaxor ferroelectric Pb_0.89La_0.11(Zr_0.7Ti_0.3)_0.9725O₃ and antiferroelectric Pb_0.93La_0.07(Zr_0.82Ti_0.18)_0.9825O₃ ceramics were designed near the antiferroelectric-ferroelectric phase boundary line in the La₂O₃-PbZrO₃-PbTiO₃ phase diagram. Conventional solid state reaction processing was used to prepare the two compositions. The ECE properties were deduced from Maxwell relations and Landau-Ginzburg-Devonshire (LGD) phenomenological theory, respectively, and also directly controlled by a computer and measured by thermometry. Large electrocaloric efficiencies were obtained and comparable with the results calculated via the phenomenological theory. Results show great potential in achieving large cooling power as refrigerants.

(Ba_1−xSr_x)(Mn_yTi_1−y)O₃(BSMT) ceramics withx= 35, 40 mol% andy= 0, 0.1, 0.2, 0.3, 0.4, 0.5 mol% were prepared using a conventional solid-state reaction approach. The dielectric and ferroelectric properties were characterized using impedance analysis and polarization-electric field (P–E) hysteresis loop measurements, respectively. The adiabatic temperature drop was directly measured using a thermocouple when the applied electric field was removed. The results indicate that high permittivity and low dielectric losses were obtained by doping 0.1–0.4 mol% of manganese ions in (BaSr)TiO₃(BST) specimens. A maximum electrocaloric effect (ECE) of 2.75 K in temperature change with electrocaloric strength of 0.55 K·(MV/m)⁻¹was directly obtained at ∼21 °C and 50 kV/cm in Ba_0.6Sr_0.4Mn_0.001Ti_0.999O₃sample, offering a promising ECE material for practical refrigeration devices working at room temperature.

Oil spilling has been a serious problem in the world for a long time, which can bring toxic substances to marine life. A large number of researchers around the world have introduced many measures to address this problem. One of the effective methods to remove oil from the oil/water mixture is to absorb oil from the mixture. Here, we prepared porous poly(lactic acid) (PLA) membranes using the electrospinning approach with different sized syringe needles, and used these membranes to absorb oil from the top of the water. It was found that the diameter of the needle has a big impact on the size and structure of the pores on the PLA fibers. The oil absorption capacity of membranes increases with a decreasing needle diameter due to the increased pore volume and specific surface area. The highest absorption capacity reached was 42.38 g/g for vacuum pump oil, 28.17 g/g for peanut oil, and 6.74 g/g for diesel oil.