Figure 3
Photo-mediated hierarchical transitions from single-molecule chirality to a macroscopic cholesteric LC phase. (a) Schematic representation of the transition from polyisocyanate with an M-helix structure to a cholesteric LC assembly. (b) Schematic representation of photo-mediated conformational transition of the poly(n-hexyl isocyanate) (PHIC) backbone, triggered by the chiroptical molecule appended at the terminus of the polymer chain. (c) Photo-mediated supramolecular helical pitch of the cholesteric LC phase with different magnitudes and signs. (d) Optical micrographs of a thin film of (2′S)-(P)-PHIC in toluene before (1) and after UV irradiation with different exposure times: (2) 25 min, (3) 45 min, (4) 90 min (5) and 150 min. (6) The irradiated sample left in the dark overnight, which exhibits the transition process from the P-helical LC phase to the M-helical LC phase, as illustrated in (c). Adapted from Pijper et al.37 (2008 ACS).
