The nano-confinement realized by lipid bilayers presents a unique system that is of fundamental interest for crystallization studies, since the lipid membrane resembles an anisotropic solution featuring a gradient of molecular order. This type of confinement is substantially different from the confinement in emulsion droplets, nanoparticles or porous materials. The interaction of purely hydrophobic molecules with lipid membranes has been addressed in a number of simulation studies, many of which were inspired by the increasing accumulation of nanoplastics in the environment . However, there is a lack of experimental studies related to this topic, partly due to the fact that such systems are challenging to prepare experimentally. In contrast to the partial insertion of amphiphilic or polyphilic molecules, the addi-tion of purely hydrophobic polymers often leads to pore formation in the membrane, or phase separation of the components . The first experimental studies date back to the 1980s with the work of Pope and coworkers on the inclusion of n-alkanes in lipid membranes. These studies suggested that n-alkanes with chain lengths higher than 18 carbons are nearly immiscible with the lipid acyl tails. Later, squalane has been found to incorporate in the bilayer center of DOPC/DOPG membranes and Bochicchio et al. demonstrated the effect of polystyrene 25-mers on DPPC membrane dynamics, thermal and mechanical properties using calorimetry, Xray and neutron scattering . Very recently, we showed with 2 H NMR that about 3-5vol% of n-triacontane (C30) can be incorporated into dipalmitoylphosphatidylcholine (DPPC) or dimirystoylphosphatidylcholine (DMPC) membranes . This system is a perfect starting point for investigating the crystallization of hydrophobic, chain-like molecules inside lipid membranes.