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The rate of heterogeneous ice nucleation on an ice-nucleating agent depends, amongst others,on the surface charge of the particle. Despite the known importance of this charge for icenucleation, still many open questions remain. We combine droplet-freezing assay studies withvibrational sum frequency generation SFG spectroscopy to correlate the interfacial waterstructure to the surface nucleation strength [1]. We focus on nucleation at atmosphericallyrelevant surfaces like alumina, silica, and mica. The surface charge is varied by changing thepH of the aqueous solution. We find that charge-induced templating of the water moleculesat the Al2O3 (0001) surface suppresses nucleation, irrespective of the sign of thesurface charge. Heterogeneous nucleation is most efficient for the nominally neutralsurface. Moreover, we observe at different substrates at the moment of freezing, atransient response with a significantly different intensity with a lifetime betweenseveral seconds and several minutes [2]. We demonstrate that this transient signal isnot originating from a transient phase of ice, as we can account for the signal bya simple combination of the time-dependent liquid and ice linear and nonlinearresponses.[1] Abdelmonem, A.; Backus, E. H. G.; Hoffmann, N.; Sánchez, M. A.; Cyran, J. D.; Kiselev,A.; Bonn, M. Surface-Charge-Induced Orientation of Interfacial Water SuppressesHeterogeneous Ice Nucleation on α-Alumina (0001). Atmos. Chem. Phys. 2017, 17,7827-7837. DOI: 10.5194/acp-17-7827-2017.[2] Abdelmonem, A.; Backus, E. H. G.; Bonn, M. Ice Nucleation at the Water–SapphireInterface: Transient Sum-Frequency Response without Evidence for Transient Ice Phase. TheJournal of Physical Chemistry C 2018, DOI: 10.1021/acs.jpcc.8b07480. [ABSTRACT FROM AUTHOR]