凯发

Graphene based materials are a rapidly expanding research area [1-2]. Applications include printable antennas [3], and electrodes in (opto)electronic [4] or energy storage devices [5]. However, the current production routes of graphene by sonication [6] or high shear-mixing [7] give low concentrations of few layer graphene (<0.2 g/L) [2,7] and require time consuming centrifugation to remove the non-exfoliated graphite flakes [2,6,7]. Here we exfoliate graphite in aqueous sodium deoxycholate (SDC) solutions using a microfluidic processor (Fig.1a) under high shear 9.2x107 s-1 turbulent flow conditions. A flow rate of 0.12 L/min gives a production rate of 0.26 g/h for single/few layer graphene flakes (thickness <4 nm) and 6.2 g/h for ~12 nm thick flakes (total flakes concentration 100 g/L). The produced material without centrifugation (yield by weight, Yw=100%) is stabilized by addition of carboxymethylcellulose (CMC) (Fig.1b) to formulate conductive printable inks suitable for blade coating, flexographic or screen printing. The inks are used for the fabrication of conductive fibers (Fig.1c) using a wet spinning process, coatings (Fig.1d) using flexo/screen printing, and aerogels (Fig.1e) using freeze drying.