Resonance in Chirogenesis and Photochirogenesis: Colloidal Polymers Meet Chiral Optofluidics

Abstract

Metastable colloids made of crystalline and/or non-crystalline matters render abilities of photonic resonators susceptible to chiral chemical and circularly polarized light sources. By assuming that μm-size colloids and co-colloids consisting of π- and/or σ-conjugated polymers dispersed into an optofluidic medium are artificial models of open-flow, non-equilibrium coacervates, we showcase experimentally resonance effects in chirogenesis and photochirogenesis, revealed by gigantic boosted chiroptical signals as circular dichroism (CD), optical rotation dispersion, circularly polarized luminescence (CPL), and CPL excitation (CPLE) spectral datasets. The resonance in chirogenesis occurs at very specific refractive indices (RIs) of the surrounding medium. The chirogenesis is susceptible to the nature of the optically active optofluidic medium. Moreover, upon an excitation-wavelength-dependent circularly polarized (CP) light source, a fully controlled absolute photochirogenesis, which includes all chiroptical generation, inversion, erase, switching, and short-/long-lived memories, is possible when the colloidal non-photochromic and photochromic polymers are dispersed in an achiral optofluidic medium with a tuned RI. The hand of the CP light source is not a determining factor for the product chirality. These results are associated with my experience concerning amphiphilic polymerizable colloids, in which, four decades ago, allowed proposing a perspective that colloids are connectable to light, polymers, helix, coacervates, and panspermia hypotheses, nuclear physics, biology, radioisotopes, homochirality question, first life, and cosmology.

Synchronization in Non-Mirror-Symmetrical Chirogenesis: Non-Helical π–Conjugated Polymers with Helical Polysilane Copolymers in Co-Colloids

“…HPS had efficient helicity/chirality transfer capability to several FL-based polymers in the co-colloids. Furthermore, the enhanced CD and CPL signal amplitudes from several FL-based polymers led by HPS almost retained, even after a complete removal of HPS by an HPS-selective photoscissoring upon 313-nm irradiation for a short period [25].…”

“…However, an intimate connection between classical/modern optics and colloids was not fully understood until recently [25]; colloids work as µm-size resonators that can boost chiroptical signals by several orders of magnitude. In macroscopic solid-state optics, mm-/cm-size ball and half-ball lenses are commonly used to efficiently collect incident light and focus emitted light into other devices.…”

“…The idea of fusion between neutral and charged colloids, coacervates, chirogenesis, WGM, and optofluidics prompted us to investigate chiroptical characteristics in the ground and photoexcited states of several µm-size chromophoric and/or luminophoric colloidal polymers with high RIs, like helical/non-helical σ-conjugated dialkypolysilanes (PSis) and helical/non-helical π-conjugated dialkylpolyfluorene (PF) derivatives, with help of surrounding chiral-and-achiral fluidic medium with a tuned lower RI to maximize WGM effect [25]. These optofluidic colloidal polymers cause resonantly-enhanced chiroptical signals such as circular dichroism (CD), circularly polarized luminescence (CPL), and CPL excitation (CPLE) spectral signals.…”

“…These optofluidic colloidal polymers cause resonantly-enhanced chiroptical signals such as circular dichroism (CD), circularly polarized luminescence (CPL), and CPL excitation (CPLE) spectral signals. Ultraweak chiroptical signals, in which the degree of circular polarization (g) is ~10 -4 (5 × 10 -3 %) from several PSis and π-conjugated polymers at the ground and photoexcited states in homogeneous solutions significantly boosted CD, CPL, and CPLE signals by three-to-five orders of magnitudes up to g ~0.7 (35%) when colloidal polymers are dispersed in the tuned RI optofluidic medium [25]. These results encouraged us to further design several µm-sized co-colloids comprising helical/chiral dialkylpolysilane homopolymers (HPSs) and non-helical/achiral π-conjugated FL-based polymers as suspension state in the tuned RI optofluidic medium [25].…”

“…If UV-C/VUV light is irradiated on a protein-DNA complex, DNA will preferentially degrade, but proteins might survive. Artificially designed co-colloids comprising photoscissable polysilane and non-photoscissable FL-polymers are suitable models of the protein-DNA complex [25,66,67].…”