Flexible solid-state cooling devices with high efficiency are attracted to ferroelectric polymers with excellent negative electrocaloric(EC)effects.It is challenging to obtain a large negative EC effect in ferroelectr...Flexible solid-state cooling devices with high efficiency are attracted to ferroelectric polymers with excellent negative electrocaloric(EC)effects.It is challenging to obtain a large negative EC effect in ferroelectric polymers due to the lack of tunable techniques.A giant negative EC response was obtained in the poly(vinylidene fluoride-trifluoroethylene)copolymers(P(VDF-TrFE),70/30,in mole ratio)irra-diated with high-energy X-ray.The irradiated P(VDF-TrFE)films showed an adiabatic temperature change of-13.5 K at 40 MV/m under a dose of 5 Mrad(1 Mrad=10^(4) J/kg)obtained by the indirect method.This significant negative EC effect is attributed to the enhancement of crystalline due to the entry of polymer molecules into the amorphous to crystalline structure and the reduction of heat ca-pacity due to the increase of crosslinking.In addition,X-ray irradiation improves the dielectric coefficient from 15 to 22.This research indicates that irradiation can modify the negative EC properties of ferro-electric polymers for solid-state cooling.展开更多
基金supported by Guangdong Basic and Applied Basic Research Foundation(2023A1515012638)Shenzhen Natural Science Funds for Distinguished Young Scholar(No.RCJC20210706091949018)+2 种基金Guangdong Provincial Key Laboratory Program(No.2021B1212040001)of the Department of Science and Technology of Guangdong Provincethe National Natural Science Foundation of China(Nos.11864046)the Basic Research Program of Yunnan Province(Nos.202001AT070064)。
文摘Flexible solid-state cooling devices with high efficiency are attracted to ferroelectric polymers with excellent negative electrocaloric(EC)effects.It is challenging to obtain a large negative EC effect in ferroelectric polymers due to the lack of tunable techniques.A giant negative EC response was obtained in the poly(vinylidene fluoride-trifluoroethylene)copolymers(P(VDF-TrFE),70/30,in mole ratio)irra-diated with high-energy X-ray.The irradiated P(VDF-TrFE)films showed an adiabatic temperature change of-13.5 K at 40 MV/m under a dose of 5 Mrad(1 Mrad=10^(4) J/kg)obtained by the indirect method.This significant negative EC effect is attributed to the enhancement of crystalline due to the entry of polymer molecules into the amorphous to crystalline structure and the reduction of heat ca-pacity due to the increase of crosslinking.In addition,X-ray irradiation improves the dielectric coefficient from 15 to 22.This research indicates that irradiation can modify the negative EC properties of ferro-electric polymers for solid-state cooling.
