Study On The Preparation And Properties Of Polydiacetylene –base Reversible Thermochromic Materials

The bule polydiacetylenes(PDAs) are produced by X-ray, UV or ? irradiation of colourless self-assembled diacetylene monomers. Polydiacetylenes changes its color from blue to red when it was stimulated by heat, organic solvents or inorganic anions, so it has been widely developed as colorimetric chemicalsensors. In this thesis, introduce about the structure of polydiacetylenes, its optical properties, mechanism of colorimetric transformation. On the other hand, reviews three kinds of polydiacetylene reversible thermochromic materials including as small molecule compound modified polydiacetylenes, polydiacetylenes/inorganic composite materials and polydiacetylenes /common polymer blend. Based on these works, we fabricated polydiacetylene- base reversible thermochromic materials.(1) The diacetylene derivative was synthesized via the esterification of 10,12-pentacosadiynoic acid with 4-aminophenol and thermochromic properties of the polymer solutionA novel diacetylene derivative was synthesized via the esterification of 10,12-pentacosadiynoic acid with 4-aminophenol, The polymer are produced by UV irradiation colourless self-assembled diacetylene derivative monomer at room temperature. The monomer was characterized by means of 1H NMR and 13 C NMR, the morphology of polymer vesides was observed by SEM, the size of the vesicles was measured by instrument of particle size. The molecule weight of the polymer was valued by means of Gel permeation chromatograph. Investigations suggested that the vesicle of polymer demonstrated a reversible blue-to-purple colorimetric transition when the temperature cyclically ranged from 25? to 70?. The color reversibility can be repeated for more than 8 heating-cooling cycles. These results show that the reversible change remained stable.(2) Prearation of the Pentacosadiynohydrazide/organic montmorillonite composite materials being reversible in the thermochromismA 10,12-Pentacosadiynohydrazide monomer was synthesized by reaction of 10,12-pentacosadiynoic acid with hydrazine hydrate, and the monomer was introduced into organic montmorillonite that was modified With cetyl trimethyl ammonium bromide by an ion exchange method. The Pentacosadiynohydrazide andOrganic montmorionite Composite materials was formed by UV irradiation the monomer of self-assembly in montmorionite at room temperature. The Composite materials were characterized by FT-IR, EA, XRD. Chang of the maximum absorption wavelength of the Composite materials was observed by ultraviolet diffuse upon heating. The results of studies suggest that the composite materials demonstrated a reversible purple red to orange colorimetric transition when the temperature cyclically ranged from 30? to 90?and the materials also exhibit high thermal stability.(3) Prearation of the pentacosadiynoic acid 2-aminoethylamide/ organic montmorillonite Composite materials being reversible in the thermochromismThe 10,12-pentacosadiynoic acid 2-aminoethylamide(PCDA-NH2) was prepared by reaction of the 10,12-pentacosadiynoic acid with ethylenediamine, the pentacosadiynoic acid 2-aminoethylamide / organic montmorillonite composite materials were synthesized by Intercalating method. The composite materials were characterized by FT-IR, TG, XRD, SEM. Chang of the maximum absorption wavelength of the composite materials was observed by ultraviolet diffuse during a heating procedure. The composite materials had a maximum absorption wavelength around 649 nm at 30?, when the materials displays the Dark blue. At 100 ?, the 649 nm absorption completely disappeared and the maximum absorption peak reached 536 nm, responsible for the red color. The composite materials demonstrated a reversible purple red to red colorimetric transition between 50?and 100?. The reversible purple red to red changes can be repeated for more than 5 heating-cooling cycles.