Tunable and selective areal polymer chain alignment method is developed for spin-cast blend fi lms of poly(3-hexylthiophene)(P3HT):[6,6]-phenyl-C61-butlyric methyl ester (PCBM) system by a femtosecond laser process. The chain alignment, phase separation, and molecular structure of the laser exposed P3HT:PCBM fi lms are investigated by grazing incidence wide angle X-ray scattering and micro-Raman analysis. The alkyl chains of P3HT polymer become highly ordered along the polarization axis of the laser. Thus, the amount of desirable face-on confi guration for solar cell application is largely enhanced with a subsequent postannealing process. Vertically expanded morphology up to 200 nm on P3HT:PCBM fi lms is also prompted by the laser irradiation without deteriorating intramolecular structure and changing chemical composition. Simultaneously, vertical phase separation of PCBM toward surface is induced at exposed region.

The crystal structure of nylon 56 fibers post extended by drawing process was investigated by synchrotron x-ray scattering measurement. In as-cast fiber, distinct (004) and (020) diffraction peaks were observed and they were related to initial metastable alignment of nylon molecules. With increase in the drawing ratio, (110) peak intensity was increased in vertical direction with decreasing (020) peak. At the same time, (004)' peak evolved position tilted to 29 degrees from the (004) peak. This evolution is directly related to stable crystalline phase of nylon 56 originated from additional formation of hydrogen bondings between N-H and C=O by post drawing process. We also compared density variation, stress-strain curves of the fiber as a function of drawing ratio and strain. The variations of density and tanacity also supported the increase of stable structure of nylon 56.

We present new technique for nano-structuring of conducting polymers using femto-second (fs) laser in P3HT:PCBM films with special chain alignment. In an optimized condition of fs laser (1030 nm) irradiation on P3HT:PCBM films, the surface changed into a photoexpanded structure. The crystalline order of edge-on P3HT decreased, while the crystalline order of face-on P3HT increased in the photoexpanded area. The chain alignment of face-on P3HT was affected by the polarization direction of irradiated laser. The PCBM amount also increased in the photoexpanded area in comparison with the pristine area. The results of micro RAMAN measurement confirmed the stability of P3HT chains under the laser irradiation, i.e the main P3TH chains were kept its chain configuration and bonds after laser in photoexpanded areas. These results imply that orientation of P3HT crystals can be selectively controlled into face-on configuration by the fslaser irradiation.

We investigated the evolution of crystal formation as a function of drawing ratio in poly(1,4-diaminobutane-co-adipic acid-co-ε-caprolactam-co-diethylenetriamine)(nylon 466T) copolymer formed by four monomers, i.e 1,4-diaminobutane, adipic acid, ε-caprolactam, diethylenetriamine(DETA), using synchrotron X-ray scattering measurement. In case of pristine(as spun) nylon 466T fiber, it was consisted with unoriented nylon 6α and unoriented nylon 46αphases. As increase the drawing ratio, unoriented nylon 6α was transformed to oriented γ phase, while unoriented nylon 46αchanged to oriented 46 α phase. The effect of the addition of DETA was not observed in the pristine fibers.However, DETA affected to restrict the formation of crystals at the maximum drawing condition, and as a result it had a role to increase the moisture regain.

Front Cover: Tunable and selective areal polymer chain alignment method is developed for conducting polymer blend films of poly(3‐hexylthiophene)(P3HT):[6,6]‐phenyl‐C61‐butyric methyl ester (PCBM) system via direct femtosecond laser writing. Interestingly, the P3HT polymer become highly ordered with face‐on configuration along the polarization direction of the laser. Further details can be found in the article by S. Chae, K. H. Jo, S. W. Lee, H.‐S. Keum, H. J. Kim,* J. Choi,* H. H. Lee* on page 537.