3D Porous Graphene Based Aerogel for Electromagnetic Applications

Abstract

Lightweight multifunctional electromagnetic (EM) absorbing materials with outstanding thermal properties, chemical resistance and mechanical stability are crucial for space, aerospace and electronic devices and packaging. Therefore, 3D porous graphene aerogels are attracting ever growing interest. In this paper we present a cost effective lightweight 3D porous graphene-based aerogel for EM wave absorption, constituted by a poly vinylidene fluoride (PVDF) polymer matrix filled with graphene nanoplatelets (GNPs) and we show that the thermal, electrical, mechanical properties of the aerogel can be tuned through the proper selection of the processing temperature, controlled either at 65 °C or 85 °C. The produced GNP-filled aerogels are characterized by exceptional EM properties, allowing the production of absorbers with 9.2 GHz and 6.4 GHz qualified bandwidths with reflection coefficients below −10 dB and −20 dB, respectively. Moreover, such aerogels show exceptional thermal conductivities without any appreciable volume change after temperature variations. Finally, depending on the process parameters, it is shown the possibility to obtain water repellent aerogel composites, thus preventing their EM and thermal properties from being affected by environmental humidity and allowing the realization of EM absorber with a stable response.

Waterproof Graphene-PVDF Wearable Strain Sensors for Movement Detection in Smart Gloves

“…As a consequence, the PVDF/GNP composite film morphology varies notably with respect to the one of the neat PVDF, from a round shape structure to a more compact configuration. Hence, the film porosity decreases noticeably, improving the waterproofness of the nanocomposite [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44] and its mechanical and electrical characteristics [39,40]. Indeed, it has also been found that GNPs have a nucleation effect on the PVDF structure, constraining the polymer chains to orient and close pores [39][40][41][42][43][44][45].…”

“…Due to their outstanding properties, GNP-filled polymer composites have been widely investigated in various engineering applications, including electromagnetic compatibility [18][19][20], structural sensing and monitoring [21][22][23][24]. Different polymer matrices have been explored, such as polystyrene [17,20], epoxy-based vinyl ester resins [18,19,24], polydimethylsiloxane [5,22], polyurethane [25], and polyvinylidene fluoride (PVDF) [23,24,[26][27][28]. Among them, PVDF is garnering ever growing interest for sensing applications owing to its uncommon chemical resistance and thermal mechanical physical properties, including piezoresistive and piezoelectric ones [29,30].…”

Mechanical properties of aerospace epoxy composites reinforced with 2D nano-fillers: current status and road to industrialization

“…Graphene and its derivatives can be used as building blocks to make such 3D structures. Graphene aerogels, also commonly known as aerographene, are widely used in polymer composites to enhance thermal [170,171], electrical [172,173], tribological [174,175] and mechanical properties of the polymer. For example, Kim et al [176] reported a maximum improvement of 76% in the fracture toughness of non-oxidized graphite aerogel (NOGA)/epoxy composite at a loading level of 0.45vol.% as compared to neat epoxy.…”

Polyvinylidene Fluoride Aerogels with Tailorable Crystalline Phase Composition

“…In this work, we tackled these challenges by developing a direct method to produce highly porous bulk PVDF aerogels with precise control of the phase composition, without further sample processing or the incorporation of a template. The limited available research on PVDF aerogels is focused on porous membranes [ 27 , 28 , 29 ], adsorbent media [ 30 , 31 , 32 ], composites [ 33 , 34 , 35 ], thermal insulation [ 36 ], and airborne particle filtration [ 16 , 37 ], mostly prepared by phase separation approaches using different solvents, followed by supercritical drying process, or in some cases by freeze drying, without meaningful attention on controlling the crystalline phases, somehow demonstrating that this porous system is seemingly ignored for piezoelectric applications. Consequently, an in-depth study on phase control has not been reported yet.…”