Cast polarized spectra

Fig.27. )P and absorption spectra of an MOPPV LB film. Open and solid circles show value of x(3) of the MOPPV LB film in the direction parallel and perpendicular to the dipping direction. Open triangles show x of an MOPPV cast film. Solid and broken lines show the absorption spectra measured by the polarized light parallel and perpendicular to the dipping direction, respectively. Dotted line shows an absorption spectrum of the MOPPV cast film.

An important breakthrough in PPy chemistry was the discovery by Lee and coworkers95 in 1995 of a chemical polymerization route to an unsubstituted PPy that was soluble in organic solvents. They exploited the surfactant-like qualities of added dodecylbenzenesulfonate (DBSA 9) as a dopant anion to solubilize PPy formed during oxidation of pyrrole by aqueous (Nn4)2S208. The PPy/DBSA product, isolated as a black powder in 42% yield after 40 h reaction at 0°C, was very soluble in m-cresol, and could be dissolved in weakly polar solvents such as chloroform and dichloro-methane by the addition of an equimolar amount of dodecylbenzenesulfonic acid. A film cast from chloroform solution exhibited an electrical conductivity of 5 S cm-1, and its UV-visible spectrum was similar to that of electrochemically deposited PPy. 

Figure 4.1 Comparison of the IR (upper) and Raman (lower) spectra of nylon-6,6. The IR spectrum was obtained by transmission through a film cast from formic acid, while the Raman spectrum was obtained from a chip of polymer. Note the domination of bands due to polar (amide) groups in the IR data, while the Raman spectrum is dominated by backbone and C-H modes. In fact, below 1650 cm the Raman spectrum is reminiscent of that of polyethylene.

---