Differentiating bulk nanobubbles from nanodroplets and nanoparticles

History has shown that it is not as easy one might think to differentiate between bulk nanobubbles and nanodroplets or nanoparticles. It generally detect colloids (i.e. something looks different, e.g. scatters light differently than its surrounding solvent), but less determine the nature of these colloids. This led misinterpretations in literature, where nanoparticles have mistakenly been assumed be nanobubbles. In this paper, we review a multitude experimental methods approaches prove existence We conclude combinations optical detection with physical perturbations such pressure ultrasound, phase-sensitive holographic are most promising convenient approaches.