Structure and properties of chiral poly(3-substituted thiophene) langmuir-blodgett films

Chiral Langmuir-Blodgett (LB) films were fabricated from mixed monolayers containing regioregular poly(3-[2-((S)-2methylbutoxy) ethyl]thiophene) ( HT -P(S)MBET) and stearic acid (SA) with different molar ratios. The HT -P(S)MBET was an optically active polymer with the head-to-tail linkage of larger than 93 %. From the UV-Vis spectra and X-ray diffraction measurements, it was found that the HT -P(S)MBET in the LB film form a layered structure in which the main chains are oriented parallel to the plane of the substrate and exhibit a tendency to orient along the dipping direction. The in-plane conductivity of the HT -P(S)MBET/SALB film doped with SbCl 5 was 1.2S cm −1 . The observed value of the third-order nonlinear susceptibility at the exciton resonance peak was in the order of 10 −7 –10 −8 esu.