One can readily evaluate the shell thickness ∆R of a droplet using the PDPS strategy, as shown in Fig. . Given the volume of a sphere, V ∝ R 3 , one can derive the skin volume ratio to the entire sphere, Fig. shows the droplet size dependence of supercooling for ice formation resolved using differential scanning calorimetry (DSC) and nuclear magnetron resonance spectroscopy (NMR) . The trend of TN depression depends on the skin volume ratio, ∆TN(R) ∝ = F(R), which clarifies that the skin O:H nonbond softening inside the skin is responsible for nanodroplets supercooling for ice formation.