Self‐Assembled Lipids as Soft Dielectrics

ABSTRACT

Lipid membranes are ubiquitous structures in nature that enable efficient charge separation and electrochemical gradients across interfaces. Despite recent progress in understanding the structural properties of lipid membranes, the electronic properties of lipid assemblies in the solid state are not fully understood. Here, we show that dehydrated lipid assemblies serve as soft dielectric materials for molecular electronics. Polymer‐supported lipid bilayers are prepared on gold electrodes via vesicle fusion, yielding uniform films with sub‐nanometer roughness determined by atomic force microscopy (AFM). The dielectric properties of dehydrated lipid assemblies are characterized using the soft‐contact liquid‐metal eutectic gallium‐indium (EGaIn) technique. Capacitance measurements in a parallel‐plate geometry enable determination of the dielectric constant of lipid bilayers, which is systematically tuned via molecular structure, composition, and assembly conditions. Lipid assemblies formed with increased cholesterol content or at lower temperatures exhibit reduced surface roughness, consistent with enhanced molecular ordering upon dehydration. These results highlight the role of self‐assembly on the structural and electronic properties of dehydrated lipids and establish new avenues for biologically inspired soft dielectrics.