Solvent-free nanofluids are generally referred to as the nanohybrids that consist of a rigid core and soft organic shell

where the shell is typically fabricated by grafting flexible charged organic oligomers to the surface of nanostructures. This novel gallery of hybrid material shows remarkable liuqid-like behavior in absence of any solvent at ambient temperature. With respects to the characteristic ionic bond that supports the core/shell building blocks

they can be regarded as nanoscale ionic materials or supermolecular ioni liquids. Meanwhile

the unique liquid manner also wins them the name of self-suspended nanoparticles and dry nanofluids. In this contribution

recent advances in researches on solvent-free nanofluids

including their microstructures

typical features and flowing mechanism along with the applications of 0-2D and macromolecular nanofluids have been reviewed.