Low-Temperature Reversible Thermochromic Polydiacetylene/Zinc(II)/Zinc Oxide Nanocomposites for Colorimetric Sensing

Abstract

A series of reversible thermochromic polydiacetylene/zinc­(II) ion/zinc oxide (PDA/Zn2+/ZnO) nanocomposites have been prepared using seven types of diacetylene monomer. The shortening of the PDA alkyl tail from 12 to 6 methylene units systematically decreases color-transition temperature (T CT) from 90 to 30 °C. Increasing the photopolymerization time during the preparation process further reduces the T CT down to 10 °C. The shortening of alkyl segment adjacent to PDA headgroup causes unpredictable changes of T CT. X-ray diffraction reveals variation of the molecular tilting angle within the bilayer structure of PDA depending on the length of alkyl segment. Infrared and Raman spectroscopies also detect the change of local interactions and backbone conformation within the nanocomposites. Our study provides a guideline for preparing reversible thermochromic materials with T CT ranging from 10 to 90 °C. These nanocomposite materials can be utilized in various applications such as colorimetric sensors, smart labels, and thermochromic inks/paints that change color in the hot, cold, or ambient conditions.

Solid‐State Low‐Temperature Thermoresponsive and Reversible Color Changes of Conjugated Polymer in Layered Structure: Beyond Infrared Thermography

“…A couple of previous works reported the color changes of PDA derivatives in the range of 223–273 K (Figure S1, Supporting Information). [ 49–52 ] The present PDA‐(L‐Arg) showed the thermo‐responsive and reversible color changes in the wider and lower temperature ranges compared with these previous works. This unusual color‐changing behavior originates from the conjugated polymer embedded in the flexible layered structure.…”

Fabrication of polydiacetylene particles using a solvent injection method

“…This means that the system can be engineered for greater sensitivity by the selection of shorter chain length monomers. This phenomenon has been documented in systematic studies of the impact of monomer characteristics on sensing properties 18,[27][28][29][30] and has been demonstrated in volatile organic compound detection using PDA. 31 We then subjected PDA composed of HCDA to different ammonia concentrations (0-2000 ppm) (Fig.…”

Fabrication of chiral polydiacetylene nanotubes via supramolecular gelation of a triterpenoid-derived amphiphile

“…On the basis of this d-spacing (47.44 Å) and the fully stretched molecular length of PCDA (L 0 = 31.1 Å, Figure S3A), the tilting angle (θ) of PCDA molecules with respect to the lamellar plane was estimated to be 49 o in Figure S3B. 35,36 As for C4-MOP assemblies, the reflection peaks appeared at 1.99, 4.56, 14.01, 21.52, and 23.88 o in Figure 4B with d-spacing of 44.34, 20.06, 6.31, 4.12, and 3.72 Å, calculating the ratio of 1: 1/5: 1/7: 1/11: 1/13. That is to say, the interlayer distance of C4-MOP was 44.34 Å.…”