Gas Release as an Efficient Strategy to Tune Mechanical Properties and Thermoresponsiveness of Dynamic Molecular Crystals

Stimuli-responsive crystals of piperazinium trifluoroacetate exhibit (1) plastic deformation readily upon stressing and (2) jumping upon heating. Moreover, the controlled release of volatile coformer (trifluoroacetic acid, jumping-mate) from the lattice helps to tune both functionalities [1 and 2] efficiently by partially preserving the system's integrity. A new crystal engineering strategy to gain further control over multi-stimuli-responsive crystals to build next-generation smart and adaptive materials is established. AbstractDynamic molecular crystals combining multiple and finely tunable functionalities are attracting and an increasing attention due to their potential applications in a broad range of fields as efficient energy transducers and stimuli-responsive materials. In this context, a multicomponent organic salt, piperazinium trifluoroacetate (PZTFA), endowed with an unusual multidimensional responsive landscape is reported. Crystals of the salt undergo smooth plastic deformation under mechanical stress and thermo-induced jumping. Furthermore, via controlled crystal bending and release of trifluoroacetic acid from the lattice, which is anticipated from the design of the material, both the mechanical response and the thermoresponsive behavior are efficiently tuned while partially preserving the crystallinity of the system. In particular, mechanical deformation hampers guest release and hence the macroscopic jumping effect, while trifluoroacetic acid release stiffens...
Source: Small - Category: Nanotechnology Authors: Tags: Research Article Source Type: research