Coatable 2D Conjugated Polymers Containing Bulky Macromolecular Guests for Thermal Imaging

Abstract

Dynamic properties are derived from the structural flexibility of 2D polymers. Softening layered structures has the potential for tuning and enhancing the dynamic properties. In the present work, the flexibility of layered polydiacetylene (PDA) is tuned by the interlayer polymeric guests with different branching structures. PDA shows thermoresponsive color-change properties through shortening the effective conjugation length with molecular motion. Whereas the blue-to-red color transition is observed at certain threshold temperatures for the layered PDA without the interlayer guest, the intercalation of the bulky polymer guests lowers the starting temperature and widens the temperature range for the thermoresponsive color changes. The resultant layered composite of PDA and bulky polymer affords the homogeneous coating on substrates on the centimeter scale. The thermoresponsive color-change coating is applied to temperature-distribution imaging. The specific heat of liquids is colorimetrically estimated using the coating on the bottle. The coating on a silk cloth visualizes the temperature distribution on a simulated tissue during surgical operation using an ultrasonic coagulation cutting device. The coating can be applied to thermal imaging in a variety of fields. Moreover, the softening strategy contributes to explore dynamic properties of soft 2D materials.

Imaging of Accumulated Mechanical Stresses Using Self-Assembled Layered Conjugated Polymer

“…In the PU matrix, the self-organized layered crystal of PCDA, not the dispersed state at the molecular level, is required to achieve the topochemical polymerization. The homogeneous dispersion of the PDA crystals is significant to prepare colorimetric sensing devices. ,, These observations indicate the homogeneous dispersion of the PDA-(PEG-PEI) crystals in the PU matrix (Figure c–e). The reference samples, such as PDA-PEI and PDA-PEG, were prepared for comparison (Figure S2 in the Supporting Information).…”

“…PDA shows visible color changes in response to external stimuli, such as thermal and chemical stresses. − The blue-to-red color change has potential for visible and colorimetric sensing. PDA-based materials and devices have been designed for sensing chemical and thermal stresses. − Although the frictional stresses induce the color changes of PDA, − the color is not changed by the other mechanical stresses, such as compression and tensile stresses. A recent study using atomic force microscopy indicates that a layered PDA based on self-assembled amphiphilic diacetylene (DA) molecules has responsiveness only to shear stress applied in the lateral direction to the lamellar .…”

A highly sensitive friction-imaging device based on cascading stimuli responsiveness

“…PDA can be easily coated on a variety of substrates, such as paper, glass, and polymer substrates. 48,55,56,[59][60][61] We have developed the coating methods, such as deposition from the solution phase, 59 dipping in the precursor solution, 48,55,56 precipitation from the colloidal liquid, 60 and spraying of the precursor solution, 61 in previous works. Moreover, the stimuli responsivity was tuned by the intercalated guests in the interlayer space.…”

Nanoarchitectonics of Exfoliated Flexible Nanosheet Based on Laterally Stacked Macrocycles

“…PDA shows color changes in response to external stimuli, such as heat, light, and force. [25][26][27][28][29][30][31][32][33][35][36][37][38][39][40] The molecular motion induces the torsion of the PDA main chain by shortening the effective conjugation length. The color change in the macroscopic appearance originates from the change in the torsional angle of the PDA main chain in molecular level.…”

“…[34] The tunable color-change and/or conductive properties of PDA have been extensively studied for sensing applications. [25][26][27][28][29][30][31][32][33][35][36][37][38][39][40] In recent years, ultrathin 2D nanostructures of PDA have been synthesized by bottom-up and top-down approaches. [41][42][43][44] Self-assembly of the specifically designed amphiphilic and macrocyclic DA monomers formed the colloidal nanosheets exhibiting the stimuli-responsive colorchange properties.…”