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Ultralight graphene/phenolic resin composite aerogels (GPFs) were prepared through the chemical reduction and self-assembly of graphene oxide (GO) in water-soluble phenolic resin, followed by a freeze-drying process; carbonized foams (GPFs(T)) were obtained by the subsequent heat treatment of GPFs at a relatively low temperature (500–700 °C). Although GPFs do not show the qualified reflection loss value of below −10dB, GPFs(T) achieve the greatly enhanced electromagnetic-wave absorbing performance. Specifically, the minimum reflection loss value of GPF1 (500) reaches −22.7 dB at 14.4 GHz with the absorber thickness of 2.0 mm and the effective absorption bandwidth is up to 5.4 GHz (12.4–17.8 GHz). The evolution of electromagnetic-wave absorbing properties from GPFs to GPFs(T) at different temperatures related with different graphene content is explored. GPFs(T) are expected to exhibit high thermal stability and excellent corrosion resistance property, and especially still maintain ultralight nature (e.g the density of GPF1 (500) is only 24.3 mg/cm3). Most importantly, little graphene (as low as 7.5 wt% of GO addition for GPF1(T)) in GPFs(T) guarantees the facile formation of three-dimension (3D) skeleton network and greatly cut downs the carbonization temperature of phenolic resin to achieve the required electromagnetic-wave energy losing ability. The present work provides an effective method to fabricate an ultralight material with exceptional performances including the good electromagnetic-wave absorbing property and the high stability.

The heat conduction of thermal interface materials (TIMs) is derived from the transport of electrons and phonons in the materials. Investigation on the thermal transport of electrons and phonons in TIMs will aid in promoting the advancement of TIMs with high performance. In this review, we summarize the current strategies for regulating the thermal transport of electrons and phonons during the preparation of TIMs. The interplay between the polymer matrix and fillers and the thermally conductive network formed by fillers is discussed. In addition, we present some new thermal measurement techniques to measure the interfacial thermal resistance. The reduction of interfacial thermal resistance is helpful for obtaining TIMs with larger thermal conductivity. Finally, we provide possible future research directions for the material design and measurement of interfacial thermal resistance.

With the miniaturization, high power density, and high integration of modern electronics, heat accumulation has emerged as a critical issue that affects their performance and reliability. The application of thermal interface materials is a common thermal management strategy. Herein, we report thermally conductive and insulating thermal interface materials composed of core-shell structured Al@Al2O3 and epoxy resin. The composites exhibit thermal conductivity of 0.92 W m−1 K−1 at 60 wt% filler contents, which is about 4.2 times higher than that of the epoxy resin. The oxidation of Al particles results in the formation of dense nanoscale insulating Al2O3 shell, which effectively restricts the electron transfer, thus leading to a very high electrical resistivity and puncture voltage of the composites. The polymer composites filled with Al@Al2O3 particles have excellent insulation property, high thermal conductivity and outstanding thermos-mechanical performance, which could be a potential thermal interface material in advanced electronic packaging techniques.

Owing to its unique properties, such as electrical insulation, high thermal conductivity, high breakdown strength, physical and chemical stability, boron nitride has been used widely as fillers to improve the thermal conductivity of polymers. However, the addition of very small boron nitride leads to a dramatic increase of viscosity of polymer composites. The increased viscosity will limit the amount of boron nitride in polymers, which results in limited increase of thermal conductivity for polymer composites. To this end, we developed a spray-assisted self-assembly method to prepare spherical boron nitride. The spherical boron nitride improves the thermal conductivity of polydimethylsiloxane, in contrast to boron nitride platelets, which is attributed to its structural characteristics. The thermal conductivity of spherical boron nitride/polydimethylsiloxane is up to 2.30 W/mK, almost four times of that of platelet-like BN/polydimethylsiloxane composite at the 50 wt% filler content. This simple and versatile method is therefore directly relevant to the future design of practical polymer composites for heat removal of modern electronics.

Boron nitride nanotubes (BNNTs), structural analogues of carbon nanotubes, have attracted significant attention due to their superb thermal conductivity, wide bandgap, excellent hydrogen storage capacity, and thermal and chemical stability. Despite considerable progress in the preparation and surface functionalization of BNNTs, it remains a challenge to assemble one-dimensional BNNTs into three-dimensional (3D) architectures (such as aerogels) for practical applications. Here, we report a highly compressive BNNT aerogel reinforced with reduced graphene oxide (rGO) fabricated using a freeze-drying method. The reinforcement effect of rGO and 3D honeycomb-like framework offer the BNNTs/rGO aerogel with a high compression resilience. The BNNTs/rGO aerogels were then infiltrated with polyethylene glycol to prepare a kind of phase change materials. The prepared phase change material composites show zero leakage even at 100 °C and enhanced thermal conductivity, due to the 3D porous structure of the BNNTs/rGO aerogel. This work provides a simple method for the preparation of 3D BNNTs/rGO aerogels for many potential applications, such as high-performance polymer composites.

Polymer composites with high thermal conductivity are attracting increasing interest as thermal-management materials owing to material abundance, easy processing and low cost. However, conventional preparation of thermally conductive polymer composites through adding high-loading inorganic fillers usually suffers from poor mechanical properties. Here, inspired by the microstructure of natural nacre, we report on fine ordered Ag-BN/epoxy resin composites via interfacial manipulation of boron nitrides with Ag nanoparticles and hot-pressing induced orientation process. The as-prepared nacre-like compounds have both high thermal conductivity (up to 23.1 W m−1 K−1) and mechanical strength (tensile strength of 80.3 MPa). This work provides a novel insight into the fabrication of polymer composites with superior mechanical strength in thermal management field.

Enhancing the thermal conductivity of polymers is important for their critical applications in all heat exchangers and electronic packaging. However, owing to the existence of interfacial thermal resistance (ITR), the overall thermal conductivity of the polymer composites cannot meet the requirements of the electronics industry. Here, we propose an approach to decreasing the ITR by both improving the contact area and the interconnection between fillers. An increase in out-of-plane thermal conductivity (0.804 W m−1 K−1) is observed in the silver nanoparticles (AgNPs)-boron nitride nanosheet (BNNS)/silver nanowires (Ag NW)/epoxy composites, which is 2.4 times higher than that of the BNNS/epoxy composites. Fitting the measured thermal conductivity of composites with Foygel model indicates that ITR can be reduced effectively when the contact and the interactions of the fillers is optimized. The proposed design methodology here potentially paves the way for designing and preparing higher thermal conductive materials in the future.

Dielectric polymer composites consisting of inorganic fillers and polymers have wide applications in high energy density electronic devices. However, development of dielectric polymer composites with enhanced energy storage density and thermal conductivity is desired but challenge. Herein, we report polymer composites consisting of epoxy resin and silver nanoparticle-decorated Al2O3 microspheres (Al2O3-AgNPs), which show enhanced energy storage density and thermal conductivity (1.11 W/m K), at 70 wt% Al2O3-AgNPs. The discharged energy density of Al2O3-AgNPs/epoxy resin composites with 70 wt% hybrid fillers is 4.28 × 10-3 J cm−3, while the composites without AgNPs is 3.09 × 10-3 J cm−3 at 200 kV cm−1. The enhanced energy storage density and thermal conductivity are attributed to the enhanced the interfacial polarization and the bridge role of AgNp in facilitating the heat flow across the interfacial boundary, respectively. The results support the potential applications of the Al2O3-AgNPs/epoxy resin composites used as dielectric materials in modern electronics and electric power systems.

As a widely used anticancer drug, doxorubicin (DOX) could induce cell death mainly via interfering with DNA activity; thus, DOX could perform therapeutic effects mainly in the cell nucleus. However, most of the reported drug delivery systems lacked the well localization in the nucleus and released DOX molecules into the cytoplasm. Due to formidable barriers formed in the nuclear envelope, only around 1% of DOX could reach the nucleus and keep active. Therefore, DOX molecules were inevitably overloaded to achieve the desired therapeutic efficacy, which would induce serious side effects. Herein, we developed a highly localized drug nanocarrier for in situ release of DOX molecules to their action site where they could directly interfere with the DNA activity. In this work, we used cationic polymer-modified upconversion nanoparticles (UCNPs) as the luminescence core and gene carrier, while aptamers served as the DNA nanotrain to load DOX. Finally, the prepared nanotheranostic agent displayed good targetability, high cell apoptosis ratio (93.04%) with quite lower concentration than the LC50 of DOX, and obvious inhibition on tumor growth.

Conventional polymer composites normally suffer from undesired thermal conductivity enhancement which has hampered the development of modern electronics as they face a stricter heat dissipating requirement. It is still challenging to achieve satisfactory thermal conductivity enhancement with reasonable mechanical properties. Herein, we present a three-dimensional (3D), lightweight, and mechanically strong boron nitride (BN)-silicon carbide (SiC) skeleton with aligned thermal pathways via the combination of ice-templated assembly and high-temperature sintering. The sintering has introduced atomic-level coupling at the BN-SiC junction which contributes to efficient phonon transport via the newly formed borosilicate glass BCxN3-x (0 ≤ x ≤ 3) and SiCxN4-x (0 ≤ x ≤ 4) phases, leading to much lower interfacial thermal resistance. Thus, the obtained BN-SiC skeleton shows satisfactory thermal performance. The prepared 3D BN-SiC/polydimethylsiloxane (PDMS) composites exhibit a maximum through-plane thermal conductivity of 3.87 W·m-1·K-1 at a filler loading of only 8.35 vol %. The thermal conductivity enhancement efficiency reaches 220% per 1 vol % filler when compared to pure PDMS matrix, superior to other reported BN skeleton-based composites. The feature of our strategy is to allow the oriented three-dimensional skeleton to be strongly bonded by a sintered ceramic phase instead of polymer-like adhesive, namely, to improve the intrinsic thermal conductivity of the skeleton to the greatest extent. This strategy can be applied to develop novel thermal management materials that are lightweight and mechanically tough that rapidly transfer heat. It represents a new avenue to addressing the heat challenges in traditional electronic products.

Herein, we report a fabrication of epoxy resin/oriented BN composites via a facile hot-pressing strategy. Benefitting from the force exerted vertically on the BN platelets, a well-ordered BN microstructure in the composites has been achieved, which renders the prepared composites an elevated thermal conductivity up to 6.09 W m−1K−1 at 50 wt% loading, while it is only 2.44 W m−1K−1 for epoxy resin/random BN composites. In addition, the composites show an enhanced tensile strength (31.79 MPa) and Young's modulus (4.63 GPa) when comparing with epoxy resin/random BN composites at the same 50 wt% loading (21.21 MPa and 1.48 GPa). We attribute the improved thermal conductivity to the well-aligned BN platelets in higher heat conduction direction based on the anisotropic thermal conduction ability of BN. The enhanced mechanical properties are ascribed to the increased friction area along the tensile in-plane direction and the decreased defects which are easily incorporated during the fabrication process. This study sheds a light for exploring future thermal management materials to meet the increasing heat dissipation demands.

Polymer composites with high thermal conductivity have a great potential application in modern electronics, due to their light-weight, easy process, low cost and stable physical and chemical properties. Nevertheless, most polymer composites commonly possess unsatisfactory thermal conductivity, primarily because of the high interfacial thermal resistance between inorganic fillers. Herein, we report a novel method through silver-deposition on the surface of the fillers to create a silver nanoparticle “bridge”, to decrease the interfacial thermal resistance between fillers. The results demonstrate that the out-of-plane thermal conductivity of the epoxy resin/sphere alumina composites is increased to 1.304 W m−1 K−1, representing an improvement of 624% compared with pure epoxy resin. This strategy provides an insight for the design of thermally conductive polymer composites with potential to be used in next-generation electronic packaging.

Polymer composites have been widely employed as electronic packaging materials, due to their low cost, flexibility, chemical stability, and high malleability, etc. However, the thermal conductivity of polymer composites becomes increasingly requirement, with the rapid growth of electronics toward miniaturization and high-power density. Conventional method to enhance the thermal conductivity of polymer is addition of high-content thermally conductive fillers, but it will deteriorate other significant properties of polymers, such as optical, electrical, and mechanical performance. Herein, we report an ice-templated assembly strategy to construct three-dimensional thermally conductive networks of BN nanosheets (BNNS) and silver nanowires (AgNWs) in epoxy resin composites. The thermal-conduction pathway can be easily built by the synergistic effects between two-dimensional BNNS and one-dimensional AgNW. Furthermore, the welding of the adjacent AgNWs through low-temperature sintering process enlarges the total contact area per unit filler volume. The resulted polymer composite thus exhibits a through-plane thermal conductivity of 1.10 Wm −1K−1 at only about 5.0 vol% fillers content, which is six times higher than that of the pure epoxy resin. This work shows great potential in advanced packaging materials, such as substrate materials and printed circuit board materials.

Flexible thermoelectric materials that can harvest waste heat energy have attracted great attention because of the rapid progress of flexible electronics. Ag2Te nanowires (Ag2Te NWs) are considered...

In the modern microelectronic devices, one of the most important challenges is efficient removal of heat via thermal interface materials. The interface problem between fillers and polymer is an important issue that restricts the thermal conductivity of thermal interface materials. Herein, we introduce plasma treatment technology to treat the surface of carbon fibers (CFs) to improve the interfacial compatibility between CFs and polymer matrix. The introduced polar oxygen-containing functional groups can promote the intermolecular bonding and the compatibility between the CFs and polymer matrix after the plasma treatment, thereby improving the thermal conductivity of the composites. At the CFs loading of 30 wt%, the CFs/PDMS composites show a better through-plane thermal conductivity (0.43 Wm−1K−1) compared to that of untreated CFs/PDMS composites (0.35 Wm−1K−1). Plasma treatment technology which is environmentally friendly has less damage to fillers and has broad application prospects.

Inspired by the preparation process of traditional tofu, we propose a tofu-based porous carbon (PC) preparation strategy. The PC (SPI-PC-x, x refers to the magnitude of pressure) with a three-dimensional (3D) structure is obtained by using soy protein isolate (SPI) with abundant protein content as raw material, and the best electrochemical performance can be optimized by adjusting the external pressure. We explored the regulation mechanism of pressure on the pore structure and the transport mechanism of electrolyte in the porous structure, aiming to provide a research basis for the fabrication of porous carbon or porous carbon composite with the action of protein (e.g SPI) flocculation. The results showed that PC with a suitable pore length has a higher effective specific surface area (SSA) and a faster ion transmission rate. The SPI-PC-200 has the maximum Cg of 280F g−1 in the three electrodes system with 6 M KOH as the electrolyte, and it has a good energy density of 16.5 Wh kg−1 when the power density is 450.0 W kg−1 in the two electrodes system with 1 M Na2SO4 as the electrolyte.

As one of the critical components in thermal management system, high thermally conductive polymer composites is the key factor affecting the heat dissipation of electronic devices. During the past few decades, considerable researches have been done to enhance the thermal conductivity of polymer composites by adding fillers with high thermal conductivity, such as metals, carbon-based materials and ceramics. Boron nitride (BN) has been considered as an ideal thermally conductive filler for polymer composites. However, the large interfacial thermal resistance at the filler-matrix interfaces and the filler-filler interfaces has greatly hampered the heat conduction, resulting in the limited improvement in thermal conductivity. In this mini review, we attempt to present recent progress in fabricating high thermally conductive polymer/boron nitride composites by constructing three-dimensional networks. We started from introducing the thermal conduction mechanism in polymer composites, and then briefly discussed the factors influencing the thermal conductivity of polymer composites, followed by presenting different fabrication methods of constructing three-dimensional networks in polymer/boron nitride composites to increase the thermal conductivity. We hope this mini review would provide some beneficial inspiration for improving the thermal conductivity of polymer composites.

Polymer composites with favorable dielectric properties and energy density are eager for energy storage application in electrical and electronic industry. Among various high-dielectric fillers, inorganic nanowires with high aspect ratio exhibit an excellent ability to enhance permittivity and energy storage density of polymers. Herein, we report ordered orientation of surface modified silicon carbide nanowires (SiCNWs) in epoxy resin via bar coating method. The relationship of ordered orientation and aspect ratio of SiCNWs with permittivity, breakdown strength, and energy density of the polymer composites was investigated. Owing to the ordered orientation of SiCNWs and their enhanced compatibility with epoxy resin, the prepared SiCNWs/epoxy resin composite possesses an enhanced permittivity (16.79), low dielectric loss (0.05), and a high energy density (29.5 × 10−3 J/cm3 under 200 kV/cm). Finite element simulation demonstrates that the ordered orientation of SiCNWs in epoxy resin not only attenuates the electric intensity but also prolongs the breakdown pathway. This work paves a new approach to preparation of polymer composites with enhanced permittivity and energy density in energy storage application.

Thermal management has become one of the most important issues for electronic devices due to the continual increase in power density and consumption. Thermal interface materials (TIMs), applied between heat sources and heat sinks, are essential ingredients of thermal management. Carbon fibers are promising fillers because of its numerous advantages including high thermal conductivity, high strength-to-weight ratio, desired fatigue resistance, and corrosion resistance. However, they are rarely considered in preparing TIMs at present, because the one-dimensional structure of carbon fibers largely enhance the viscosity of the composites using conventional methods, and thus increase the complexity of processing. Herein, we report a thermally conductive TIM based on the construction of three dimensional and vertically aligned carbon fibers (3D-CFs) skeleton. The 3D-CFs skeleton is fabricated by vertical freezing the solution of CFs followed by freeze-dying to remove the ice and then infiltrating them with epoxy resin matrix. At a relatively low CFs loading of 13.0 vol%, the composites show an enhanced through-plane thermal conductivity (2.84 W m−1 K−1) compared to that of a neat epoxy resin (0.19 W m−1 K−1). Theoretical models qualitatively demonstrate that the interfacial thermal resistance is mainly originated from CFs–CFs interface not CFs–epoxy interface in oriented CFs/epoxy composites. In addition, the composites also possess a low thermal expansion coefficient (CTE) of 23.63 ppm K−1, and an increased glass transition temperature of 222.8 °C at a relatively small CFs loading (13.0 vol%) compared to that of pure epoxy resin. Our fabrication of through-plane assembly of carbon fibers skeleton has broad application prospects in TIMs.

With the fast development of the integrated circuit towards high density, miniaturization, multifunctionalization, heat management become one of the top priority issues to be addressed. Owing to excellent physical and chemical properties, especially excellent flexibility, polymers have wide applications in electronic. Nevertheless, most polymers possess thermal conductivity below 0.5 W/mK, which cannot meet the requirement in modern electronics with high power density and high speed. Conventionally, thermally conductive fillers are used to enhance the polymers’ thermal conductivity. Unfortunately, the enhancement of thermal conductivity is limited even at the high-volume fractions of filler (50% in volume). Herein, we report on an effective approach to preparing Al 2 O 3 -AgNP hybrids liquid-phase chemical reduction method. The Al 2 O 3 -AgNP hybrids consist of silver nanoparticles (AgNP) decorated aluminum oxide (Al 2 O 3 ) microball. The structure and morphology of Al 2 O 3 -AgNP hybrids were confirmed. We demonstrated that the Ag nanoparticles with the size of 40–50 nm were uniformly decorated on the Al 2 O 3 surface, and the amount of Ag nanoparticles also can be tunable. We believe that this method has potential in preparing Al 2 O 3 -based polymer materials for application in thermally conductive polymer composites.

Stanozolol is one of the most widely used synthetic anabolic steroids but also presents a host of negative side effects. It is necessary to develop a rapid and sensitive method for stanozolol screening to monitor its abuse. In this study, the polyclonal antibody against stanozolol was prepared and a novel indirect competitive chemiluminescence enzyme immunoassay (CLEIA) for stanozolol was developed. The stanozolol hapten was conjugated to proteins to prepare immunogen and coating antigens, firstly. To improve the performances of the method, the chemiluminescent detection system was optimized. The optimal concentration of 4-iodophenol, hydrogen peroxide and luminol was studied and the proper detection time was also investigated. Under the optimal conditions, the IC50 value and the limit of detection (IC20) of the chemiluminescence immunoassay is 0.34 and 0.07 ng/mL in phosphate-buffered saline (PBS), respectively. The accuracy performances of the proposed CLEIA were compared with that of ELISA and HPLC. Different nutraceuticals, foodstuffs, and biological matrices spiked with stanozolol were applied to study the application of the proposed assays, and the average recoveries locate at 92–113 % with the coefficients of variation of 8–13.5 %. The polyclonal antibody-based chemiluminescence immunoassay formats are proved to be a feasible and reliable quantificational method for stanozolol.