Ultrathin boron nitride nanosheets (BNNSs) were prepared at 300°C by a new variable-pressure one-step synthesis. An increase in pressure during the synthesis results in a decreased thickness for the nanosheets, which were all triangular in shape with zig-zag edges. The synthesized nanosheets exhibit high adsorption capacities for the organic dye methylene blue (MB). In addition to these properties, the BN nanosheets can be used as excellent thermal-conducting additives in BN-polymer ...