Abstract: This specification presents sheets including graphitic materials, including sandwich structures, thermoformed or wet-formed single layer or multilayer structures of graphitic materials, and methods of forming a layer of graphitic material. In accordance with one aspect, the specification presents a multi-layer structure comprising a core layer having a core density between 0.01 and 1 g/cm3; and a skin layer covering the core layer, the skin layer having at least 10% by weight of a graphitic material, the graphitic material having one or more of graphene oxide, reduced graphene oxide, graphene, graphite oxide, reduced graphite oxide and graphite, the skin layer having a skin density of between 0.5 and 2 g/cm3 , a thickness ratio of the skin layer to the core layer being of between 1:1000 and 1:1.

Abstract: There is provided a graphene-based membrane where the mechanical properties, thermal conductivity, electrical conductivity, and/or three-dimensional curvature of the membrane have been tuned according to the desired application of the membrane. Methods of accelerating the vacuum-assisted self-assembly (VASA) process for graphene-based membranes and methods for accelerating the process of removing liquid from a graphene-based dispersion are also provided. The method can include two steps of reduction to both minimize the filtration time and to substantially restore the electrical and thermal properties of a graphene-based membrane at low temperature.

Abstract: There is a composite material for an acoustic transducer diaphragm comprising: a thermoplastic polymer resin, a graphitic filler, and optionally a coupling agent. The thermoplastic polymer resin is selected from the group consisting of polypropylene, polyethylene, poly(methyl methacrylate), polycarbonate, polyoxymethylene, cyclic olefin copolymer, polyethylene terephthalate, acrylonitrile butadiene styrene, polybutylene terephthalate, polyamide, poly(ADP-ribose) polymerase, polyethylenimine, polyamide-imide, polyether ether ketone, polyolefin, polyester, polycarbonate, polysulfone, polyacetals, polyvinyl acetals, polyketone, polyamides, cyclic olefin copolymer, thermoplastic thermotropic liquid-crystal polymer, polyphenylene sulfide, polyimide and a mixture thereof. The graphitic filler is selected from the group consisting of graphene oxide, reduced graphene oxide, graphite, graphene and carbon nanotubes, and a mixture thereof.

Abstract: This specification presents sheets including graphitic materials, including sandwich structures, thermoformed or wet-formed single layer or multilayer structures of graphitic materials, and methods of forming a layer of graphitic material. In accordance with one aspect, the specification presents a multi-layer structure comprising a core layer having a core density between 0.01 and 1 g/cm3; and a skin layer covering the core layer, the skin layer having at least 10% by weight of a graphitic material, the graphitic material having one or more of graphene oxide, reduced graphene oxide, graphene, graphite oxide, reduced graphite oxide and graphite, the skin layer having a skin density of between 0.5 and 2 g/cm3 , a thickness ratio of the skin layer to the core layer being of between 1:1000 and 1:1.

Abstract: There is provided a graphene-based membrane where the mechanical properties, thermal conductivity, electrical conductivity, and/or three-dimensional curvature of the membrane have been tuned according to the desired application of the membrane. Methods of accelerating the vacuum-assisted self-assembly (VASA) process for graphene-based membranes and methods for accelerating the process of removing liquid from a graphene-based dispersion are also provided. The method can include two steps of reduction to both minimize the filtration time and to substantially restore the electrical and thermal properties of a graphene-based membrane at low temperature.

Abstract: The method can include depositing a graphene oxide containing material from solution to form a laminar nano-structure of graphene oxide paper, and assembling at least a portion of the graphene oxide paper as a diaphragm of the acoustic transducer. The acoustic transducer can be a magnetic induction based microphone, a diaphragm loudspeaker, or a magnetic induction based loudspeaker, for instance.

Abstract: Materials used in acoustic transducer membranes need very specific qualities that in any real system require many tradeoffs to be made. Graphene and graphene related materials are a newly discovered class of materials with some exceptional properties that offer the potential for significant contributions to the performance of many acoustical transduction systems. Accordingly the inventors have established graphene oxide based transducers as the basis of ribbon microphones and diaphragm loudspeakers using low cost manufacturing and processing techniques.