Molecular-level design of excellent reversible thermochromic polydiacetylene materials with the simultaneous enhancement of multiple performances

Abstract

Recently, colorimetrically reversible materials have been paid significant attention, not only to gain a better understanding of the fundamentals of their chromism, but also to create the ways of overcoming...

Fluorescein-Functionalized Conjugated Polydiacetylenes with Excellent Reversible Thermochromic Properties under Thermal and 980 nm Near-Infrared Light Stimuli

“…Furthermore, the temperature-dependent FTIR spectra were explored to gain deep insight into the thermochromic property of the FPDA material; the FTIR spectra of the FPDA film were obtained at 30 and 150 °C and cooled back to 30 °C. As shown in Figure and Figure S8, the peak at 3300 cm –1 corresponded to the stretching vibration of −OH, the characteristic peak at 1645 cm –1 was assigned to amide CO stretching, and the absorption peaks at 1560 and 1466 cm –1 corresponded to the C–N stretching vibration and the scissoring band of the CH 2 groups . When heated to 150 °C, the intensities of the peaks at 3300, 1645, 1560, and 1466 cm –1 decreased gradually, indicating the reduction of hydrogen bonding interactions for FPDA .…”

“…As shown in Figure 5 and Figure S8, the peak at 3300 cm −1 corresponded to the stretching vibration of −OH, the characteristic peak at 1645 cm −1 was assigned to amide C� O stretching, and the absorption peaks at 1560 and 1466 cm −1 corresponded to the C−N stretching vibration and the scissoring band of the CH 2 groups. 2 When heated to 150 °C, the intensities of the peaks at 3300, 1645, 1560, and 1466 cm −1 decreased gradually, indicating the reduction of hydrogen bonding interactions for FPDA. 1 When the temperature cooled back to 30 °C, the intensity of the peaks at 3300, 1645, 1560, and 1466 cm −1 was recovered mostly without a frequency shift, thus confirming the recovery of hydrogen bonding between the headgroups from the red phase to blue phase transfer.…”

“…In nature, chromism is a significant phenomenon found in many biological systems, such as chameleons, Kallima inachus, Pacific tree frogs, and octopuses, which can adjust the colors of the skin in response to external stimuli. , Therefore, scientists have been inspired by enormous interest in the development of stimulus-responsive colorimetric materials. Among these materials, conjugated polymers have been widely investigated owing to their extensively delocalized π-electron networks as well as unique optical and electric properties. − The special structures endow the conjugated material with excellent sensitive properties to environmental stimuli, which make them ideal candidates in the design of chemical and biological sensors. − …”

“…Temperature is essential to daily life and acts as the common environmental stimulation for thermochromic materials owing to its potential applications for smart devices. , To date, a number of studies have been investigated to exhibit distinct reversible thermochromic transitions focused on PDA sensors, and the key strategy for the design of PDA-based materials with reversible colorimetric transitions is to introduce strong interactions, including aromatic interactions or hydrogen bonding between the headgroups. ,,,− Yoon and Chen designed a DA monomer with a phenylacetamide head, and the strong π–π stacking between acetamide and DA monomers led to intermolecular H bonding, which possessed colorimetric reversibility in the range of 30–70 °C in both the aqueous and solid states . In addition, they also synthesized bis-polydiacetylenes linked with p -phenylene groups, and the intermolecular H bonding of PDA endowed bis-PDA with reversible color change properties over a larger temperature range between 20 and 120 °C .…”

Ultra-low-temperature reversible thermochromism and contactless bacterial sensing by chalcone-functionalized polydiacetylene

“…42 In the case of HCl-treated chalcone-PDA, the strong intramolecular interactions between the HCl-associated chalcone residues, mediated by hydrogen bonding and electrostatic ion pair affinity, likely facilitates both structural flexibility accounting for the different colors even at very low temperatures, as well as the thermochromic reversibility facilitated through retaining the interactions between the headgroups. 43 Importantly, reversible low-temperature thermochromism was not observed in the case of simple PDA prepared from 10,12-tricosadiynoic acid (Fig. S5, ESI †), underscoring the significance of the chalcone headgroup for this intriguing phenomenon.…”