Characterization of Colloidal Amorphous Arrays Prepared by Uniaxial Pressure Application

• DOI: 10.1021/acs.langmuir.9b02622
• Publication Date: 2019-10-01T16:39:17Z
• Authors: Yui Naoi; Takahiro Seki; Ryosuke Ohnuki; Shinya Yoshioka; Yukikazu Takeoka
• Keywords: 01 natural sciences; 0104 chemical sciences

We prepared a colloidal amorphous array by applying uniaxial pressure to a powder of monodispersed colloidal silica particles. Pellet-shaped samples were obtained that exhibit different structural colors depending on the diameter of the particles. We characterized the optical properties of the arrays by measuring the angle-dependent scattering spectrum wherein several spectral peaks were observed. The peak at the longest wavelength was caused by the short-range order of the particle arrangement. Interestingly, this peak exhibited a smaller shift in wavelength than that observed in similar samples prepared by several different methods. The other spectral peaks were thought to originate from Mie scattering, which produces a color when the diameter of the colloidal particles is appropriately chosen. Our results showed that uniaxial pressure application can be a suitable method to prepare structurally colored pigments with low angle dependence.