Mechanism of photomechanical deformation of β-lead azide whisker crystals

Mechanically Responsive Molecular Crystals

“…74,75 Nevertheless, although still limited in number relative to polymer materials, there is an emerging number of instances of elastic and mechanically compliant organic crystals with remarkable mechanical response. 4,45,76,77 Within this line of pursuit, it recently has been shown 78−80 that under mechanically applied force, certain organic molecular crystals can respond with impressive mechanical properties; 81 for instance, they can be bent elastically or plastically over 180°8 2 or to 360°8 3,84 or can even be superelastic, 85,86 much like superelastic inorganic materials. The mechanical properties of single crystals under external mechanical force were summarized in a recent review article 80 and will not be a part of the focus in this Review.…”

Mechanically Responsive Organic Crystals by Light

“…Anthracenes are photochemically reactive and undergo [4 + 4] photodimerization upon UV light irradiation in solution as well as in the solid state. [51,52] Reversible photomechanical bending of nanorod crystals of 9-anthracenecarboxylic acid (11) in acidic aqueous solution was first reported by Al-Kaysi and Bardeen in 2007 (Figure 5a). [53] 9-Methylanthracene forms different crystal shapes, microneedles, microribbons, and microplates, which exhibited different motions, such as bending, twisting, and rolling-up, respectively, due to photodimerization.…”

“…Photomechanical bending was first reported in 1982 in a whisker crystal of a metal-organic complex, [9] and research on mechanically responsive molecular crystals had been developed in the 1980s. [10][11][12] Afterwards, in 2007, Irie group reported rapid and reversible bending in the rod-like microcrystals of photochromic diarylethene when irradiated with ultraviolet (UV) light, successfully linking the molecular-level shape change to the macroscopic mechanical motion of the crystals. [13] Since then, several groups have actively undertaken studies of mechanically responsive crystals for more than a decade, mainly based on photoisomerization (reversible photoreaction), and many mechanical crystals have been available at the present time.…”

Mechanically Responsive Crystals: Analysis of Macroscopic Strain Reveals “Hidden” Processes

“…Mechanical effects of dynamic crystals, 1 crystalline materials that exhibit macroscopic motion, have been documented since almost four decades ago, 2,3 and this research field was recently revived due to the fundamental research interest in such materials as well as because of their potential for applications as organic actuators. 4−9 Potential applications of molecular or microscopic mechanical switches range from wearable electronics to applications in biomedical sciences.…”