In this work, we have selected a group of short peptides containing 4-5 Ile (I) and 1 Lys (K) and examined the effects of sequential substitution of one I by L on nanostructuring. Through extensive studies by AFM and TEM, we found that sequential replacements can hugely affect nanostructures via altering peptide packing, layer thickness and twisting. This is because L disfavors hydrogen bonding whilst I encourages it. These structural effects affect how molecules can align and form layers and extend to higher orders of structures. Because these sizes are in the order of a few nanometers and difficult to image but are ideal for SANS measurements. SANS2d is preferred because of its high structural sensitivity and wider Q range to cover weak signals and different size ranges. We request 3 days of SANS2d to undertake the tasks planned.