Dielectric polymer films are energy storage materials that are used in pulse power operations, power electronics and sustainable energy applications. This paper reviews energy storage devices with focus on dielectric ...Dielectric polymer films are energy storage materials that are used in pulse power operations, power electronics and sustainable energy applications. This paper reviews energy storage devices with focus on dielectric film capacitors. Two prominent examples of polymer dielectrics Polyetherimide (PEI) and Poly (tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride) (THV) have been discussed. Polyetherimide (PEI) is an amorphous polymer recognized for its high-temperature capability, low dielectric loss and high dielectric strength. THV is a semi-crystalline polymer with high dielectric constant, high-temperature capability and charge-discharge efficiency. The primary focus of this paper is to introduce the reader to the fabrication procedures and characterization techniques used in research labs for processing of dielectric polymers. The fabrication and characterization process of both polymers has been discussed in detail to shed the light on experimental process in this area of research.展开更多
Citric acid,an important metabolite with abundant reactive groups,has been demonstrated as a promising starting material to synthesize diverse photoluminescent materials including small molecules,polymers,and carbon d...Citric acid,an important metabolite with abundant reactive groups,has been demonstrated as a promising starting material to synthesize diverse photoluminescent materials including small molecules,polymers,and carbon dots.The unique citrate chemistry enables the development of a series of citric acid-based molecules and nanomaterials with intriguing intrinsic band-shifting behavior,where the emission wavelength shifts as the excitation wavelength increases,ideal for chromatic imaging and many other applications.In this review,we discuss the concept of“intrinsic band-shifting photoluminescent materials”,introduce the recent advances in citric acid-based intrinsic band-shifting materials,and discuss their potential applications such as chromatic imaging and multimodal sensing.It is our hope that the insightful and forward-thinking discussion in this review will spur the innovation and applications of the unique band-shifting photoluminescent materials.展开更多
With the growing importance of optical techniques in medical diagnosis and treatment,there exists a pressing need to develop and optimize materials platform for biophotonic applications.Particularly,the design of bioc...With the growing importance of optical techniques in medical diagnosis and treatment,there exists a pressing need to develop and optimize materials platform for biophotonic applications.Particularly,the design of biocompatible and biodegradable materials with desired optical,mechanical,chemical,and biological properties is required to enable clinically relevant biophotonic devices for translating in vitro optical techniques into in situ and in vivo use.This technological trend propels the development of natural and synthetic polymeric biomaterials to replace traditional brittle,nondegradable silica glass based optical materials.In this review,we present an overview of the advances in polymeric optical material development,optical device design and fabrication techniques,and the accompanying applications to imaging,sensing and phototherapy.展开更多
We have investigated dielectric properties of aromatic polythiourea(ArPTU,a polar polymer containing high dipolar moments with very low defect levels)thin films that were developed on Pt/SiO_(2) substrate.The detected...We have investigated dielectric properties of aromatic polythiourea(ArPTU,a polar polymer containing high dipolar moments with very low defect levels)thin films that were developed on Pt/SiO_(2) substrate.The detected response is compared to the response of commercially available polymers,such as high density polyethylene(HDPE)and polypropylene(PP),which are at present used in foil capacitors.Stable values of the dielectric constantε'≈5(being twice higher than in HDPE and PP)over broad temperature and frequency ranges and dielectric losses as low as in commercial systems suggest ArPTU as a promising candidate for future use in a variety of applications.展开更多
High elastic energy density and high-efficiency ionic electromechanical actuators were prepared from aligned activated microwave exfoliated graphite oxide(A-aMEGO)/polymer nano-composites,and the electromechanical per...High elastic energy density and high-efficiency ionic electromechanical actuators were prepared from aligned activated microwave exfoliated graphite oxide(A-aMEGO)/polymer nano-composites,and the electromechanical performance was characterized.The elastic modulus and elastic energy density of the ionic actuators can be tuned over a wide range by varying the polymer(poly(vinylidene fluoride/chlorotrifluoroethylene)[P(VDF-CTFE)])concentration in the nano-composite actuators.The A-aMEGO/P(VDF-CTFE)nano-composite actuators with 35 wt.%of polymer content exhibit an elastic energy density higher than 5 J/cm^(3) and an electromechanical conversion efficiency higher than 3.5%,induced under 4 V.The results show the promise of high-density highly aligned graphene electrodes for high-performance ionic electromechanical transduction devices.展开更多
Fe BSi C metglas was annealed at an optimized condition（350 °C, 5 min） to achieve the mixed phases with pristine amorphous phase and crystallization phase.With such annealed metglas, a self-biased magnetoelect...Fe BSi C metglas was annealed at an optimized condition（350 °C, 5 min） to achieve the mixed phases with pristine amorphous phase and crystallization phase.With such annealed metglas, a self-biased magnetoelectric（ME） laminate of metglas/Pb（Zr, Ti）O3/metglas was fabricated. Without any external magnetic field, the composite exhibits the ME coefficient aE31 of 103 m V/（cm Oe） at1 k Hz and 15.5 V/（cm Oe） at electromechanical resonance frequency. The induced ME voltage shows a good linear relation to the applied AC magnetic field with amplitude as low as 10-7T at 1 k Hz. It is expected that such self-biased ME composites provide a practical application of economical and compact magnetic sensors.展开更多
文摘Dielectric polymer films are energy storage materials that are used in pulse power operations, power electronics and sustainable energy applications. This paper reviews energy storage devices with focus on dielectric film capacitors. Two prominent examples of polymer dielectrics Polyetherimide (PEI) and Poly (tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride) (THV) have been discussed. Polyetherimide (PEI) is an amorphous polymer recognized for its high-temperature capability, low dielectric loss and high dielectric strength. THV is a semi-crystalline polymer with high dielectric constant, high-temperature capability and charge-discharge efficiency. The primary focus of this paper is to introduce the reader to the fabrication procedures and characterization techniques used in research labs for processing of dielectric polymers. The fabrication and characterization process of both polymers has been discussed in detail to shed the light on experimental process in this area of research.
基金This work was supported in part by National Institutes of Health grants(AR072731,NS123433,HL158204,and R21EB024829).
文摘Citric acid,an important metabolite with abundant reactive groups,has been demonstrated as a promising starting material to synthesize diverse photoluminescent materials including small molecules,polymers,and carbon dots.The unique citrate chemistry enables the development of a series of citric acid-based molecules and nanomaterials with intriguing intrinsic band-shifting behavior,where the emission wavelength shifts as the excitation wavelength increases,ideal for chromatic imaging and many other applications.In this review,we discuss the concept of“intrinsic band-shifting photoluminescent materials”,introduce the recent advances in citric acid-based intrinsic band-shifting materials,and discuss their potential applications such as chromatic imaging and multimodal sensing.It is our hope that the insightful and forward-thinking discussion in this review will spur the innovation and applications of the unique band-shifting photoluminescent materials.
基金This work was supported in part by National Institutes of Health awards(EB024829,CA182670,AR072731).
文摘With the growing importance of optical techniques in medical diagnosis and treatment,there exists a pressing need to develop and optimize materials platform for biophotonic applications.Particularly,the design of biocompatible and biodegradable materials with desired optical,mechanical,chemical,and biological properties is required to enable clinically relevant biophotonic devices for translating in vitro optical techniques into in situ and in vivo use.This technological trend propels the development of natural and synthetic polymeric biomaterials to replace traditional brittle,nondegradable silica glass based optical materials.In this review,we present an overview of the advances in polymeric optical material development,optical device design and fabrication techniques,and the accompanying applications to imaging,sensing and phototherapy.
基金This project was financially supported by the Slovenian Research Agency under program P1-0125the Ministry of Education,Science,and Sport of Republic of Slovenia and European Social Fund under project PR-05648the Office of Naval Research(ONR)under Grant No.N00014-14-1-0109.
文摘We have investigated dielectric properties of aromatic polythiourea(ArPTU,a polar polymer containing high dipolar moments with very low defect levels)thin films that were developed on Pt/SiO_(2) substrate.The detected response is compared to the response of commercially available polymers,such as high density polyethylene(HDPE)and polypropylene(PP),which are at present used in foil capacitors.Stable values of the dielectric constantε'≈5(being twice higher than in HDPE and PP)over broad temperature and frequency ranges and dielectric losses as low as in commercial systems suggest ArPTU as a promising candidate for future use in a variety of applications.
基金supported by NSF under grant number CMMI-1130437 and by a grant from Korean Institute of Science and Technology。
文摘High elastic energy density and high-efficiency ionic electromechanical actuators were prepared from aligned activated microwave exfoliated graphite oxide(A-aMEGO)/polymer nano-composites,and the electromechanical performance was characterized.The elastic modulus and elastic energy density of the ionic actuators can be tuned over a wide range by varying the polymer(poly(vinylidene fluoride/chlorotrifluoroethylene)[P(VDF-CTFE)])concentration in the nano-composite actuators.The A-aMEGO/P(VDF-CTFE)nano-composite actuators with 35 wt.%of polymer content exhibit an elastic energy density higher than 5 J/cm^(3) and an electromechanical conversion efficiency higher than 3.5%,induced under 4 V.The results show the promise of high-density highly aligned graphene electrodes for high-performance ionic electromechanical transduction devices.
基金supported by the National Natural Science Foundation of China(51402164 and 51572142)
文摘Fe BSi C metglas was annealed at an optimized condition（350 °C, 5 min） to achieve the mixed phases with pristine amorphous phase and crystallization phase.With such annealed metglas, a self-biased magnetoelectric（ME） laminate of metglas/Pb（Zr, Ti）O3/metglas was fabricated. Without any external magnetic field, the composite exhibits the ME coefficient aE31 of 103 m V/（cm Oe） at1 k Hz and 15.5 V/（cm Oe） at electromechanical resonance frequency. The induced ME voltage shows a good linear relation to the applied AC magnetic field with amplitude as low as 10-7T at 1 k Hz. It is expected that such self-biased ME composites provide a practical application of economical and compact magnetic sensors.
