Figure 2. Heterogeneous nucleation kinetics of the CO₂ hydrates in the presence of hydrophobic amino acids.

Subcooling temperatures at the onset of CO₂ hydrate nucleation with glycine or PVP in (a) fresh water and (b) memory water, and with hydrophobic amino acids in (c) fresh water and (d) memory water. Memory water was prepared by dissociating preformed CO₂ hydrate at a temperature 2.5 K above the equilibrium temperature for 30 min. Measured subcooling temperature were correlated with (e) hydrophobicity and (f) alkyl side chain length for the hydrophobic amino acids. The values of the average and standard deviation are shown.