2020同步年報

038 ACTIVITY REPORT 2020 Fig. 3 : (a) 2D SAXS pattern of PS-b-P4VP(aD) 0.5 , recorded under shear align- ment in situ using a rheometer; the inset in the upper-right corner is a selected magnified zone. (b) 1D SAXS profile integrated along the equatorial direction of the 2D SAXS pattern in (a). (c) 1D SAXS profile integrated from the cross pattern in (a). (d) Azimuthal angle scan from first-order diffraction of the cross pattern. (e–g) TEM images of PS heli- ces with adjustable curliness, obtained at grafting ratios x = (e) 0.3, (f) 0.4 and (g) 0.5 in PS-b-P4VP(aD) x . [Reproduced from Ref. 1] = 0.3–0.5) in PS- b -P4VP( aD ) x . Upon increasing the grafting ratio, the corresponding apparent curliness was increased, as evident in the TEM micrographs ( Figs. 3(e)–3(g) ). This effect means that the degree of helical curliness can be hierarchically transmitted across various length scales in the DJBCP system. Notably, such adjustable curliness is rarely observed in BCP-based helical structures. In summary, this work shows the first discovery of helical structures with tunable curliness triggered from the focal asymmetry in an entirely achiral system of DJBCP through hydrogen-bonding interactions. (Reported by I-Ming Lin, National Sun Yat-sen Univer- sity and Wei-Tsung Chuang) This report features the work of Wei-Tsung Chuang, Yeo-Wan Chiang and their coworkers published in J. Mater. Chem. C 8 , 1923 (2020). This paper was select- ed as the inside front cover of Issue 6. [Cover image reproduced by permission of Wei-Tsung Chuang and The Royal Society of Chemistry from J. Mater. Chem. C, 2020, 8 , 1923, https://doi.org/10.1039/C9TC06135E.] TLS 23A1 IASW – Small/Wide Angle X-ray Scattering • SAXS • Materials Science, Chemistry, Condensed-matter Physics, Environmental and Earth Science Reference 1. I. M. Lin, C.-M. Chou, M.-C. Li, R.-H. Guo, C.-K. Lee, H.-J. Li, Y.-W. Chiang, Y.-H. Lin, Y.-C. Lee, C.-J. Su, U. S. Jeng, W.-T. Chuang, J. Mater. Chem. C 8 , 1923 (2020). structure. The distance between two helices and a pitch length estimated from the diffraction positions are ca. 140 and 125 nm, respectively, which are consistent with the TEM image. In Fig. 3(d) , the azimuthal scan of the first-order diffraction of the cross pattern reveals that the helical angle (twisting power) of the PS helix is approximately 50 o , as estimated from the angle enclosed between the arms of the cross. The twisting power of the PS helixes becomes adjustable on controlling the grafting ratio ( x