Acyl L-Carnitines are a group of novel surfactants with attractive physical and biological properties associated with their head group charge features. This work proposes to use neutron reflection as the unique technique to determine the thickness and composition of surfactant adsorbed layers at the solid/water interface. Because silica is the model substrate that has been widely used for studying protein adsorption, it has been chosen here, also due to its mimicry to glass widely used as containers for therapeutic proteins. Because the head group has special charge responses to pH, it will be of interest to examine how the adsorbed layer structure changes with pH and ionic strength. We request 3 days of Inter (or 4 days of Surf) beam time to complete the proposed measurements.