Pressure-Induced Transition of Bisamide-Substituted Diacetylene Crystals from Nonphotopolymerizable to Photopolymerizable State

Abstract

Mechanoresponsive diacetylenes (DAs) exhibiting a transition of crystalline orientation from light-inert to light-active state upon applied force are reported. Amide units are introduced to DAs where hydrogen bonding is utilized to control intermolecular interactions. Application of external pressure (2–150 MPa) to DAs results in an emergence of new crystal phases with changing the d-spacing which possibly reduces the reaction barrier. Accordingly, the dramatic crystalline transition from “perfectly off” to “on” state to undergo the light-induced topochemical polymerization of bulk DA crystals is obtained. Subsequent UV irradiation at a wavelength of 254 nm enables the polymerization of the pressed region, changing its color from white to blue which suggests the selective formation of polydiacetylene (PDA) polymorphs. In addition, by utilizing the mechanoresponsive crystallinity with low-enough activation pressure, a new strategy for PDA patterning is demonstrated based on the selective transfer of information by means of force to a DA film. This phenomenon can be applicable to a new nanoimprinting technique where no mechanical deformation of resist materials but phase transition is induced by the mold.

Mechano‐ and Photoresponsive Behavior of a Bis(cyanostyryl)benzene Fluorophore

“…Alternatively, such photochemical reactions became easier to take place in the amorphous state due to the increased free volume, resulting in photoinduced change in emission color. Recently, similar mechanically induced change in photochemical reactivity in the solid state for bisamide‐substituted diacetylene has been reported …”

“…Alternatively,s uch photochemical reactions became easier to take place in the amorphouss tate due to the increased free volume, resulting in photoinduced change in emission color.R ecently,s imilar mechanically inducedc hange in photochemicalr eactivity in the solid state for bisamidesubstituted diacetylenehas been reported. [16] Finally,w eh ave demonstrated the emissionp atterningb yu sing the phenomenon of the photoinduced emission color change. The sample film of CSB-5 was prepared by rubbing the CSB-5 powder onto at ransparent glass substrate, followed by an- Figure 9.…”

Imidazolium‐Functionalized Diacetylene Amphiphiles: Strike a Lighter and Wear Polaroid Glasses to Decipher the Secret Code

“…Successful topochemical polymerization requires the molecular alignment of the DA, which must be self‐assembled to meet specific geometric parameters. [ 26–28 ] The blue‐to‐red transition of PDA resulting from the structural distortion of the alternating ene–yne polymeric backbone by external stimuli such as heat, solvents, and mechanical stress is the most common. [ 29–35 ] PDAs have been widely proposed as ideal candidates for sensing materials, but their practical application as secret inks is quite limited because DA solutions in organic solvents should be transferred to a substrate and then evaporated for printed patterns.…”

A Series of Bisamide‐Substituted Diacetylenes Exhibiting a Terminal Alkyl Odd/Even Parity Effect on Mechanoactivated Photopolymerization

“…Recently, our group has succeeded in showcasing DA derivatives that can undergo an unprecedented phase transition from light‐inert to the light‐reactive state by mechanical pressure [13] . Introducing bisamide groups to DA molecules enabled intermolecular hydrogen bonding, which benefited monomeric assembly to enable selective photopolymerization in crystals.…”