In this work, we propose to exploit the unique capability of neutron reflection (NR) to study the structural changes of multi-component lipid monolayer models mimicking bacterial membranes upon their exposure to de novo designed ultrashort antimicrobial lipopeptides, focusing on unravelling their unusual mechanism of action. NR is the only technique that can determine the amount and distribution of these represent AMPs once adsorbed. We request 3 days on INTER using the event mode to complete this work.