TY - JOUR
T1 - Dual-colour generation from layered colloidal photonic crystals harnessing "core hatching" in double emulsions
AU - Lee, Jun Hyuk
AU - Choi, Gwan H.
AU - Park, Kyung Jin
AU - Kim, Dongjae
AU - Park, Juhyun
AU - Lee, Seungwoo
AU - Yi, Hyunmin
AU - Yoo, Pil J.
N1 - Funding Information:
This work was supported by research grants of NRF (2014 M3A7B4052200, 2014M3C1A3053035, 2017R1A2B2008132, and 2018M3D1A1058624) funded by the National Research Foundation under the Ministry of Science and ICT, Korea.
PY - 2019
Y1 - 2019
N2 - Colloidal photonic crystals (CPCs), which possess intrinsic colourization characteristics due to their internal periodic structure, have been extensively exploited for various optical applications. However, conventional droplet-based synthesis of CPCs has shown simple structure and mono-colour generating properties since they generally require a protective shell as the outermost confining layer, and the lattice spacing inside the CPCs is invariantly determined, which hinders further tunability for structural and optically responsive properties. To enhance the tunability for structural and optically responsive properties of CPCs, here, we present a means to induce a spontaneous core-hatching process of selectively removing the CPC-encapsulating oil layer in double emulsion droplets by harnessing interfacial instability. By virtue of the reinforced interconnectivity between colloidal polyvinylpyrrolidone (PVP)-decorated polystyrene (PS) nanoparticles, isolated CPCs can retain their structural integrity even without a protective outer shell. As a result, the hatched CPCs can be further re-ordered into a core-shell-like structure having dual internal spacings and dual-colour generation properties. PVP chains decorated on the PS nanoparticles dictate the lattice spacing not only through solvent swelling but also by imparting structural stability via formation of hydrogen bonds. Furthermore, the degree of hatching of CPCs can be modulated to either core-shell-like CPCs (complete hatching) or Janus-like CPCs (partial hatching). Therefore, the work presented here offers a new approach to create uniquely structured and multicoloured CPCs with stimulus responsiveness while fully utilizing the advantages of the double emulsion templating method.
AB - Colloidal photonic crystals (CPCs), which possess intrinsic colourization characteristics due to their internal periodic structure, have been extensively exploited for various optical applications. However, conventional droplet-based synthesis of CPCs has shown simple structure and mono-colour generating properties since they generally require a protective shell as the outermost confining layer, and the lattice spacing inside the CPCs is invariantly determined, which hinders further tunability for structural and optically responsive properties. To enhance the tunability for structural and optically responsive properties of CPCs, here, we present a means to induce a spontaneous core-hatching process of selectively removing the CPC-encapsulating oil layer in double emulsion droplets by harnessing interfacial instability. By virtue of the reinforced interconnectivity between colloidal polyvinylpyrrolidone (PVP)-decorated polystyrene (PS) nanoparticles, isolated CPCs can retain their structural integrity even without a protective outer shell. As a result, the hatched CPCs can be further re-ordered into a core-shell-like structure having dual internal spacings and dual-colour generation properties. PVP chains decorated on the PS nanoparticles dictate the lattice spacing not only through solvent swelling but also by imparting structural stability via formation of hydrogen bonds. Furthermore, the degree of hatching of CPCs can be modulated to either core-shell-like CPCs (complete hatching) or Janus-like CPCs (partial hatching). Therefore, the work presented here offers a new approach to create uniquely structured and multicoloured CPCs with stimulus responsiveness while fully utilizing the advantages of the double emulsion templating method.
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U2 - 10.1039/c9tc01055f
DO - 10.1039/c9tc01055f
M3 - Article
AN - SCOPUS:85067315782
VL - 7
SP - 6924
EP - 6931
JO - Journal of Materials Chemistry C
JF - Journal of Materials Chemistry C
SN - 2050-7526
IS - 23
ER -