Multicolor Reversible Thermochromic Properties of Gallic Acid-Cored Polydiacetylenes Appended with Poly(alkyl aryl ether) Dendrons

Abstract

This study describes synthesis of zero and fi rst generation poly(alkyl aryl ether) dendrons onto a gallic acid core, tethered with three diacetylene moieties and their photopolymerization. Resulting polydiacetylenes are studied by (i) UV-vis, IR, Raman spectroscopies, and chromoisomerism by naked eye visualization; (ii) their stabilities by differential scanning calorimetry, thermogravimetric method, and (iii) structure, morphology, and emission behavior by scanning electron, transmission electron, atomic force microscopies, powder X-ray diffraction method, and fl uorescence spectroscopy. The dendron-appended polydiacetylenes show robust nanoribbon morphologies and exhibit multicolor, reversible chromoisomerism at temperatures up to 300 °C. Reversibility of amide bond IR frequencies, as a function of temperature, shows the polymer stabilities, in addition to the results of thermal and powder X-ray diffraction studies. Temperature annealed polymers having red color phase exhibit emission maxima at 572 and 633 nm, that shift to higher wavelength upon heating and revert to the initial emission wavelengths on cooling.

Recent Developments in Polydiacetylene-Based Sensors

“…When the carboxylic group of the garlic acid was replaced with poly(alkyl aryl ether) dendrons to obtain monomer 2, the reversible thermochromism was further improved to 300 °C, as a result of enhanced interactions provided by the dendrons. 326 Alternatively, a linker was used to attach two α-D-mannopyranoside moieties at the position of the carboxylic group of the gallic acid to obtain monomer 5 that can be used for sensing, i.e., to assess the carbohydrate−protein interaction between sugar and lectin via chromic changes. It was found that the addition of the lectin concanavalin A (Con A) to PDA vesicles made from these monomers did not induce a color change of the system, even though DLS and AFM clearly showed an increase in the size of the vesicles.…”

Surface Ligand Density Switches Glycovesicles between Monomeric and Multimeric Lectin Recognition

“…Sugar ligands attached polydiacetylenes are known to undergo changes in the chromatism as a result of the ligand‐receptor interactions [42–44] . A facile formation of vesicles occurs with such ligand‐tethered polymers [44–48] . The chemical structures of glycolipid M‐L , lipid E‐L and the corresponding polymeric mixed vesicles studied herein are shown in Figure 1, synthesis and characterization are given in the Supporting Information (Section S1).…”

Surface Density of Ligands Controls In‐Plane and Aggregative Modes of Multivalent Glycovesicle‐Lectin Recognitions

“…Polymers form stable glycovesicles in a facile manner in aqueous solutions. Visual color changes of the glycovesicles upon interaction with the protein lead to derive colorimetric ratio, which defines the extent with which the polydiacetylene functionality undergoes perturbation as a result of the receptor interaction [48–53] …”