Sum-frequency spectroscopic investigation of the alignment of liquid crystals on self-assembled monolayers and imaging of endgrafted alpha-helical polypeptide films

We highlight the unique attributes of sum-frequency spectroscopy by reviewing two case studies performed in our laboratory to investigate the orientation of macromolecules at interfaces. The first case study illustrates how spectral information of sum-frequency spectroscopy can be used to probe the orientation of monolayers and also independently probe the anisotropy of a metal interface, which influences the orientation of the monolayers, buried below a monolayer. The second case study illustrates how sum-frequency spectroscopy can be used to obtain spatial information of the uniformity of distribution and the density of coverage of synthetic proteins that are deposited as thin films.