Templated Supramolecular Structures of Multichromic, Multiresponsive Perylene Diimide-Polydiacetylene Films

Abstract

We report a detailed synthesis and characterization of novel polymeric supramolecular structures composed of semiconducting perylene diimide (PDI)−imidazole templates of varying methylene spacer length (n = 3, 4, and 6) hydrogenbonded to a conjugated polymer backbone of acid-functionalized polydiacetylene (PDA), 10,12 pentacosadiynoic acid. First, a combination of molecular and morphological characterization tools confirmed that the templated supramolecular structures are a result of the synergistic effect of intermolecular PDI π−π stacking coupled with noncovalent imidazole−acid interactions. Second, a simple and scalable solid-state polymerization of the drop-cast films by UV radiation delivers multichromic, multiresponsive films capable of unique phase/morphology-switching properties with a high degree of local ordering. Thermal studies by differential scanning calorimetry and morphological studies by wide-and small-angle X-ray scattering (WAXS/SAXS, respectively) show dramatic morphological effects and trends in crystallinity with methylene spacer group extension. Furthermore, UV−vis studies displayed an unusual PDA "purple phase" transition, which was additionally verified by SAXS as a coexistence of previously known red-and blue-phase PDA. Finally, the polymerized drop-cast films displayed reversible thermo-and solvatochromic responses after a second treatment of UV radiation and additional UV-thermal cycling revealed the extent of reversibility.

A writable aniline‐functionalized polydiacetylene composite with obvious colorimetric change upon both heating and near infrared lights irradiation

“…Previous works have proved that the strong interaction among the side chains is necessary for the thermal stability of PDA and the reversible thermochromic transition property. 24,25 the absorption peak at 635 nm disappeared and the peak at 543 nm became dominant, which corresponds to the red phase of poly(PCDA-AN). It is believed that high temperature can promote the side chains dynamics and distort the π-orbital planarity arrangement along the ene-yne backbone, leading to the reduction of the effective conjugation length and thus the appearance of purple or red phase PDA.…”

Reversible Solvatochromism of Polydiacetylenes Based on Extensively Hydrogen-Bonded Tubular Arrays

“…However, scanty reports in the literature demonstrated the recovery of the blue-phase PDA from solvatochromism-induced red-phase PDA after the second treatment of UV radiation for an additional solvatochromic cycle. The reverse-phase transformation for blue-phase recovery is supposedly due to the integration of recrystallized unreacted residual DA monomers into PDA. , …”

“…46 formation for blue-phase recovery is supposedly due to the integration of recrystallized unreacted residual DA monomers into PDA. 47,48 As a part of continued efforts targeted at the development of stimulus-responsive PDAs, 49−54 we designed, prepared, and explored the first reversible color-changing (blue-purple) solvatochromic PDA. The reversible nature of the solvatochromic behavior of the new PDA is caused by a synergetic interplay between intra-and intermolecular hydrogen-bonding interactions.…”

Nickel-Ion-Coordinated Reversibly Solvatochromic Polydiacetylene Based on Tubular Assembly of Macrocyclic Diacetylene

“…Polydiacetylenes (PDAs) are a kind of polymers with unique chromogenic properties. − PDA encompasses extended π-conjugated functionality and typically absorbs light in the visible region with a brilliant blue color appearance. PDAs are intrinsically supramolecular structures and can be readily prepared via topochemical polymerization of hierarchal assembled diacetylenes (DAs) typically by using 254 nm UV irradiation or heat treatment. , PDAs endow a fascinating property of stimuli-responsiveness with the typical blue-to-red colorimetric transition and fluorescence-turn-on changes through a partial distortion of the π-conjugated backbones.…”