Two tetrapeptide derivatives [peptide A (Boc-Ala-Ile-Ile-Gly-OMe) and peptide B (Boc-Ala-Ile-Leu-Ser-OMe)], that take helical turn conformation in solution, were shown to form monolayer at the air/water interface. Circular dichroism (CD) measurements indicate that peptide A has more helical turn propensity than peptide B in sodium dodecyl sulphate (SDS) micelles. Langmuir-Blodgget film study of peptides A and B suggest that both the peptides form stable monolayer at the air/water interface. Spectroscopic investigations reveal that peptide A forms helical turn assemblage on transferring the film into hydrophilic quartz and hydrophobic ZnSe surfaces. Whereas, peptide B adopts beta-sheet structure on hydrophilic surface and a mixture of beta-sheet and helical turn conformation on hydrophobic surface. (C) 2003 Elsevier B.V. All rights reserved.