Optical Properties Study Of Polydiacetylene Assembly

Polydiacetylene (PDA) is a new kind of environmental response conjugated polymer and has a wide range of application in electronics and sensors areas. And the small diacetylene derivative molecules can self-assemble in solution to form various assembly structure, such as vesicles, tube, wire, beltand helical structure.In this work, we mainly focused on the research of color change behavior of polydiacetylene aggregates in solution and the waveguide behavior based on polydiacetylene micro tube.In the first part, we synthesized three kinds of azobenzene substituted diacetylene (AzoDA). Under the irradiation of60Co, azobenzene substituted diacetylene (AzoDA) could be polymerized into azobenzene substituted polydiacetylene (AzoPDA). Then soluble PDA could be obtained by heating reflux-reprecipitation method. We started our research on the heat and light response of AzoPDA solution with the help of FI-IR,UV-vis and TEM. As a result, the prepared three different AzoPDA has different response to heat and light. The AzoPDA aggregates which had a stronger interaction in the side chain had a higher chromatic transition temperature.The photo-isomerization of the azobenzene chromophore influenced the conformation transition of the side chains and fruit AzoPDA with photo-responsive properties. While under UV irradiation, the polymer morphology of the aggregates irreversibly changed by the block into a ball and the color of AzoPDA aggregates in solution changed from red to yellow. This work constructed a double response polymer assembly and was of great fundamental value for the rational design of novel heat and light sensor.The second part, we prepared a kind of composite vesicle with DA and its derivates. The prepared vesicles could assemble into microtube under the coordination between DA and metal ions. The formed microtube was about2-3um in the outer diameter and500nm in the tube wall, and the length of the formed microtube could even reach to several centimeters. Then we obtained the different assemble shape of DA aggregates in the different assemble period and developed a model of the formation process of microtube. Taking advantage of polarized Raman technique, we studied the chemical and congregated structure of single microtube clearly. Thus, we got to know that the PDA main chains were highly ordered and the slip angle between the orientation of PDA chains and the microtube axis was about60°. The particular structure fruited PDA microtube with anisotropic fluorescence properties. Then we studied the waveguide behavior of microtube and found that the waveguide behavior was environment-responsive. What’s more, the polarization was found to be independent on the propagation distance. This work connected polymer material with light andexpend the application prospect of polymersand provided a wide platform for the preparation of polymer microelectronic devices.