Crystal Engineering of Molecular Solids as Temporary Adhesives

Crystal engineering of temporary adhesion is important in diverse fields ranging from healthcare to manufacturing. Molecular solidsa broad class of crystalline materials characterized by discrete molecules with well-defined chemical and crystal structurescan be utilized as sublimable adhesives to achieve rapid adhesion, strong mechanical bonding, and facile on-demand release of surfaces. Through systematic investigation of the interfacial and bulk properties of molecular solids, this paper shows that this class of materials can exhibit remarkable mechanical strength (resistance to shear stress up to 2100 kPa and shear strain up to 37, as well as shear moduli up to 1000 kPa) yet enable on-demand (within minutes) release from adhesion through controlled sublimation without the application of solvents and/or mechanical force. Intermolecular interactions heavily influence the mechanical performance via preferential orientation of the solid relative to surfaces during the melt-bonding process. This research quantifies how chemical and crystal structures inform macroscopic mechanical properties of polycrystalline solids.