title: Elucidation of Chiral Symmetry Breaking in a Racemic Polymer System with Terahertz Vibrational Spectroscopy and Crystal Orbital Density Functional Theory.
abstract: The conservation of chiral symmetry has been used as a fundamental rule to determine polymer packing conformations in racemic systems. We have illustrated, through the interplay of polarization terahertz (THz) spectroscopy and solid-state density functional theory, that the chiral symmetry is not conserved in a poly(lactic acid) stereocomplex (scPLA) system. Poly(l-lactic acid) (PLLA) displays a weaker violation of the 31screw symmetry than poly(d-lactic acid) (PDLA) and possesses a stronger intramolecular vibrational energy, on average, in the low-frequency gamma-point phonon modes than does PDLA. Polarization THz spectroscopy adds a new dimension to polymer crystallography through which new phenomena are expected to be revealed.
authors: Molecular Photoscience Research Center, Kobe University , Kobe 657-8501, Japan.
authors: Feng
authors: F
authors: Zhang
authors: Center for Condensed Matter Sciences, National Taiwan University , 1 Roosevelt Road Sec. 4, Taipei 10617, Taiwan.
authors: Houng-Wei
authors: HW
authors: Wang
authors: Molecular Photoscience Research Center, Kobe University , Kobe 657-8501, Japan.
authors: Keisuke
authors: K
authors: Tominaga
authors: Center for Condensed Matter Sciences, National Taiwan University , 1 Roosevelt Road Sec. 4, Taipei 10617, Taiwan.
authors: Michitoshi
authors: M
authors: Hayashi
authors: Departments of Chemical Science and Engineering, Graduate School of Engineering, Kobe University , Kobe 657-8501, Japan.
authors: Sunglin
authors: S
authors: Lee
authors: Departments of Chemical Science and Engineering, Graduate School of Engineering, Kobe University , Kobe 657-8501, Japan.
authors: Takashi
authors: T
authors: Nishino