Department of Organic Chemistry, Indian Institute of Science, Bangalore, India
Abstract:
This study describes synthesis of zero and first 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 fluorescence 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.
