Additional profiles showing the alignment of step height and adhesion changes are shown in Figure . Across this field of view, C30H61OH crystals also show an average 8.3 nm step height, equal to two C30H61OH molecular chains end to end in contrast to the single-molecule step heights observed in C31H64 crystals. The height of two chains stacked in the idealized P21/c structure is 8.3 nm. Notably, the height of two chains in the C2/c structure is only 6.6 nm due to the tilt of the chains, suggesting the chains do not pack with C2/c symmetry when crystallized from solution onto a flat surface. Together, differences in adhesion corresponding to terraces and a preference for double-steps map to key features of the β-form C30H61OH unit cells (P21/c and P2/c). The β-form unit cells exhibit a chemically distinct two-molecule repeat, where surfaces terminated by alcohol groups are expected to exhibit different adhesion properties to methyl-terminated surfaces. The strong hydrogen bonding between alcohol groups, with hydrogen bond donor-acceptor pairs represented particularly in the P21/c structure, explains these double-step height features. Given the thermodynamically favorable hydrogen bonding interactions, unpaired or dangling alcohol groups are likely to make a significant contribution to raising the surface free energy or promoting further molecular attachment. This increases growth velocities, in comparison to methyl-terminated, van der Waals interacting surfaces. As such, double steps between methylterminated terraces appears the most likely step arrangement. These AFM observations, together with TEM and SAED analyses, provide experimental confirmation of end-to-end functional group interactions that distinguish C30H61OH crystals from C31H64 crystals despite otherwise similar chain lengths and polyethylene-like side-by-side chain packing.