Biomass-derived nitrogen-doped carbon quantum dots: highly selective fluorescent probe for detecting Fe3+ ions and tetracyclines.

How to rationally design the microstructure of polymer nanocomposites to significantly improve their electromagnetic interference shielding effectiveness (EMI SE) is still a great challenge. Herein, we developed a template method for fabricating 3D porous graphene nanoplatelets/reduced graphene oxide foam/epoxy (GNPs/rGO/EP) nanocomposites, in which 3D rGO foam embedded with GNPs constructs a 3D electrical and thermal conductive network in the EP matrix. The 3D rGO framework resolves the agglomeration problem of GNPs, acts as an efficient bunch of channels for electrical transport and attenuates the entered electromagnetic wave. Benefiting from this 3D nanohybrid framework, the GNPs/rGO/EP nanocomposites containing 0.1 wt% rGO and 20.4 wt% GNPs exhibit an EMI SE value of 51 dB in the X-band range, an almost 292% improvement relative to the rGO/EP nanocomposites (∼13 dB) and 240% enhancement compared with the GNPs/EP nanocomposites without 3D microstructures (∼15 dB) and an excellent thermal conductivity of 1.56 W mK−1 and electrical conductivity up to 179.2 S m−1. This work provides a new strategy for the design of muti-functional epoxy nanocomposites for EMI shielding and efficient heat dissipation.

Superior electromagnetic interference shielding 3D graphene nanoplatelets/reduced graphene oxide foam/epoxy nanocomposites with high thermal conductivity

There is a growing demand for stretchable strain sensors because of their potential applications in various emerging fields, such as human motion detection, health monitoring, wearable electronics, and soft robotic skin. Recently, strain sensors based on flexible conductive polymer composites (FCPCs) composed of conductive materials and a stretchable elastomer have received intensive attention owing to their high stretchability, good flexibility, excellent durability, tunable strain sensing behaviors, and ease of processing. Here, we systematically summarize the recent progress of stretchable strain sensors based on FCPCs. This review covers the classification and sensing mechanisms as well as the influence of multiple factors on the sensing behaviors of FCPC based strain sensors with detailed examples.

An overview of stretchable strain sensors from conductive polymer nanocomposites

Fluorine-containing polyimide (PI) with low dielectric constant (e) value was firstly synthesized by a polycondensation reaction of 4, 4-(hexafluoroisopropyl) diphthalic anhydride (6FDA), 1, 3, 4-triphenyldiether diamine (APB) and 1, 3-bis(3-aminopropyl) tetramethyldisiloxane (GAPD). γ-glycidoxypropyltrimethoxysilane (KH-560) and aminopropylisobutyl polyhedral oligomeric silsesquioxane (NH2-POSS) were synchronously performed to functionalize the surface of boron nitride (f-BN) fillers, which were then utilized as thermally conductive fillers to fabricate the corresponding f-BN/PI composites. NH2-POSS was successfully grafted on the surface of BN fillers. All the f-BN/PI composites presented better thermal conductivities, dielectric and thermal properties than those of BN/PI composites at the same addition of BN fillers. The obtained thermal conductivity coefficient (λ) of the f-BN/PI composites with 30 wt% f-BN was 0.71 W/mK, higher than that of BN/PI composites with 30 wt% BN (λ of 0.69 W/mK). Modified Hashin-Shtrikman model demonstrated that f-BN possessed relatively lower thermal resistance with PI matrix. Meantime, the corresponding e and dielectric loss tangent (tanδ) value of the f-BN/PI composites was decreased to 3.32 and 0.004, respectively, lower than that of BN/PI composites with 30 wt% BN (e of 3.77 and tanδ of 0.007). Moreover, the corresponding heat resistance index (THRI) and glass transition temperature (Tg) of the f-BN/PI composites was further enhanced to 280.2 °C and 251.7 °C, respectively.

Enhanced thermal conductivities and decreased thermal resistances of functionalized boron nitride/polyimide composites

Microwave solvothermal carboxymethyl chitosan templated synthesis of TiO2/ZrO2 composites toward enhanced photocatalytic degradation of Rhodamine B.

Trace electrosprayed nanopolystyrene facilitated dispersion of multiwalled carbon nanotubes: Simultaneously strengthening and toughening epoxy

Three-dimensional (3D) porous network materials with large pore volume, high specific surface area, and controllable porosity have potential application in wastewater treatment. This work aims to develop a novel hyperelastic and ultra-light magnetic reduced graphene oxide (rGO-Fe3O4) 3D framework with a density of 4.52 mg cm−3 through a covalent bond of aminated nanomagnetite (Fe3O4-NH2) onto graphene oxide (GO) and subsequent reduction. This 3D framework exhibited high adsorption capacities to ethyl acetate (215.8 ± 11.8 g g−1), cyclohexane (239.7 ± 9.9 g g−1), acetone (149.1 ± 6.5 g g−1), dichloromethane (308.0 ± 16.4 g g−1), and sesame oil (204.7 ± 10.2 g g−1), which were much higher than those of pure rGO aerogel (45.6 ± 2.3 g g−1 to ethyl acetate). Meanwhile, the 3D framework demonstrated superelastic mechanical properties with a 100% recoverability during the cyclic compression loading tests under an optimal fabrication condition of 1 mg mL−1 GO concentration and 3:1 mass ratio of GO to Fe3O4-NH2 nanoparticles. Most importantly, this rGO-Fe3O4 3D framework could achieve an effective oil/water separation within only 25 s and maintained an outstanding adsorption capability to ethyl acetate after 10 cycles of the adsorption/desorption process without any obvious change, depicting an excellent recyclability and reusability. This work aims to provide a promising material for environmental control and oil/organic solvent adsorption. Graphical abstract

Yaqing Wang

Papers

Trace electrosprayed nanopolystyrene facilitated dispersion of multiwalled carbon nanotubes: Simultaneously strengthening and toughening epoxy

Hyperelastic magnetic reduced graphene oxide three-dimensional framework with superb oil and organic solvent adsorption capability