Self-Assembled Monolayers as Nucleating Surfaces to Screen Rapidly for Polymorphs of Organic Crystals Lara A. Estroff, Cornell University, PRF #45242-G5 Aim: To assay the effects of soluble additives, in combination with functionalized surfaces, to control polymorphism in calcium carbonate. Primary Result: We have demonstrated that a peptide, n16N, is capable of promoting the growth of aragonite, the less stable polymorph of CaCO3, only when used in conjunction with b-chitin as the nucleating surface. n16N+b-chitin n16N+a-chitin Raman Significance: We have demonstrated that the nucleation surface (a vs. b chitin) alone is not sufficient to control polymorphism in calcium carbonate. When coupled with a soluble peptide additive, however, b-chitin selectively grows the less stable polymorph, aragonite. In future work, we will apply the concept of combining surfaces with soluble additives to control polymorphism in organic crystals.