Step 2: Tetraethyl orthosilicate (500 μL) was added to 10 mL of 0.1 mM aqueous solution of L-tartaric acid (pH 3.8) and prehydrolyzed at 20 °C by stirring on a roller-mixer for 7 h. Then, equal volumes of prehydrolyzed tetraethyl orthosilicate and organic gels containing the ribbons were mixed (typically, 4 mL of each) and stirred at 20 °C with a roller-mixer overnight. The excess silica precursor and organic template were washed away by i-PrOH using a centrifuge.