Programmable Twisting of Flexible Nanosurfaces with Attached Chiral Ligands

Chiral molecules attached to flexible nanoscale surfaces can interact cooperatively and deform their underlying surfaces in complex ways. Here, molecular dynamics simulations are used to model graphene ribbons with covalently attached chiral gluconic acid molecules in different crystal orders. The simulations revealed that asymmetric steric forces acting between the chiral molecules can generate stresses and torques that cause bending and helical twisting of the functionalized nanoribbons depending on their cut direction, relative sizes, ligand density, enantiomeric excess, and overall history. Upon annealing and quenching in water, the ligands can remain in the same crystalline phase, switch to a new phase, or become randomly oriented. Such deformable nanosystems can be implemented in sensing, mimicking, and memory applications.