Yuanjin Zhao 1,2* , Zhuoying Xie 1 , Hongcheng Gu 1 , Lu Jin 1 , Xiangwei Zhao 1 , Baoping
Wang, Zhongze Gu 1*
Relationships of silica nanoparticle sizes and concentrations, and the reflection wavelengths of the hybrid ETPTA.
As mentioned in the main text, in high silica nanoparticle concentrations, significant interparticle repulsion occurs at the average interparticle spacing; and the minimum energy configuration makes the colloidal nanoparticles mainly form the non-close-packed FCC colloidal crystal array (CCA) structure in the ETPTA. Due to this structure, the hybrid ETPTA solutions appear the property of photonic band gap
(PBG) and show characteristic reflection peaks. The main reflection peak position λ can be estimated by Bragg’s equation for a normal incident beam onto the (111) plane of the FCC structure:
λ=1.633
dn average
=1.633
d silica
(0.74/ν) 1/3 [ n silica
2 ν+ n
ETPTA
2 (1-ν)] 1/2 (1) where d silica
is the size of the silica nanoparticles, ν is the volume fraction of the nanoparticles in the hybrid ETPTA solutions, n silica
and n
ETPTA are the refractive index of silica nanoparticles and ETPTA, which have the similar value of 1.47. By putting this value into equal (1), we could get the relationship of λ, d silica
and ν, listed below:
λ=2.17
d silica
/ν
1/3
(2)
Therefore, by dispersing the silica nanoparticles with the diameter of 120nm, 160nm and 200nm, and with the concentration in the range from 20% to 30% (volume fraction), we could achieve the hybrid ETPTA with the reflection peaks that in all the visible light range.

Figure S1.
(a) The glass microfluidic device designed to make double emulsions where each droplet contains multiple inner cores. (b) The microscopic magnification of the dashed boundary in figure S1a shows the microfluidic inner structure, where the double emulsions generated. Scale bar is 200 μm.
Figure S2.
The polymerized double emulsions with single multi-component photonic cores due to the coalescing of the inner oil phases: (a, b) double emulsions with three-component cores; (c-f) double emulsions with Janus cores. Scale bars are 200
μm.

Figure S3.
(a) The glass microfluidic device designed to make double emulsions with the position indexable cores. (b, c) The microscopic magnification of the dashed boundary in figure S3a show the microfluidic inner structures, where the indexable cores and the double emulsions generated. Scale bars are 100 μm.
Figure S4.
The polymerized barcodes are with the position indexable photonic crystal cores. Scale bars are 200 μm.

Description of Movies:
Movie S1: Rotation of the photonic crystal barcodes under a rotating magnetic field.
Movie S2: Separation of the photonic crystal barcodes under a permanent magnetic field.