K4 fe cn 6

The chemical reagents K₃[Fe(CN)₆], K₄[Fe(CN)₆], and agar powder were purchased from Fujifilm Wako Pure Chemical Corporation. GdmCl was purchased from Tokyo Chemical industry Co., Ltd. All solutions were prepared using deionized water.

The following is a simple reaction model of the BSF reaction that is called the Rabai–Kaminaga–Hanazaki model34 35 (link):





For Figs 3, 4f,h and 5, aqueous phase 1 consisted of 150-mM KBrO₃ (Wako Pure Chemical) and 0.2-mM Fl–Na, whereas aqueous phase 2 was 30-mM K₄Fe(CN)₆ (Wako Pure Chemical), 15-mM H₂SO₄ (Nacalai Tesque) and Na₂SO₃ (Wako Pure Chemical). Thus, the final concentrations in the transporters were , , and 0.1-mM Fl–Na. was varied depending on the experiment being performed. The initial chemical concentrations in the reactor were the same as those in the transporters. All the experiments were carried out at ∼35 °C using a thermo-plate (MATS-U52RA26, Tokai Hit) on the microscope.
We used the Rabai–Kaminaga–Hanazaki model for the numerical analyses in Fig. 3e,g. The numerical analyses were performed using Mathematica (Wolfram Research). The details are given in Supplementary Note 2.