Transparent Colloidal Crystals With Structural Colours

Erdem T., O'Neill T., Zupkauskas M., Caciagli A., Xu P., Lan Y., ...Daha Fazla

FRONTIERS IN PHYSICS, cilt.10, 2022 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 10
  • Basım Tarihi: 2022
  • Doi Numarası: 10.3389/fphy.2022.847142
  • Dergi Adı: FRONTIERS IN PHYSICS
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Directory of Open Access Journals
  • Anahtar Kelimeler: colloid, structural color, SAXS (small-angle X-ray scattering), latex particle, photonic crystals, PHOTONIC CRYSTALS, PHASE-TRANSITION, HARD-SPHERE, BEHAVIOR, PROTEIN, SYSTEM, ANGLE
  • Abdullah Gül Üniversitesi Adresli: Evet

Özet

Spatially ordered arrangements of spherical colloids are known to exhibit structural colours. The intensity and brilliance of these structural colours typically improve with colloidal monodispersity, low concentrations of point and line defects and with increasing refractive index contrast between the colloids and the embedding medium. Here we show that suspensions of charge stabilised, fluorinated latex particles with low refractive-index contrast to their aqueous background form Wigner crystals with FCC symmetry for volume fractions between 13 and 40%. In reflection they exhibit both strong, almost angle-independent structural colours and sharp, more brilliant Bragg peaks despite the particle polydispersity and bimodal distribution. Simultaneously, these suspensions appear transparent in transmission. Furthermore, binary AB, A(2)B and A(13)B type mixtures of these fluorinated and similarly sized polystyrene particles appeared predominantly white but with clear Bragg peaks indicating a CsCl-like BCC structure and more complex crystals. We characterised the suspensions using a combination of reflectivity measurements and small-angle x-ray scattering, complemented by reflectivity modelling.