Novel Flexible Belt-shaped Coaxial Microcables with Tunable Multicolor Luminescence, Electrical Conduction and Magnetism

We designed a specially designed coaxial spinneret in this study. The inner stainless-steel needle was connected to the inner plastic syringe just like the traditional one. The outer stainless-steel needle was replaced by a plastic nozzle, and connected to the outer plastic syringe. The tip of the inner stainless-steel needle was shortened 2 cm from the tip of the outer plastic nozzle. This structure of the specially designed coaxial spinneret has the advantage of making sure that the highly viscous spinning solution for fabricating microcables flows easily, and the tapering shape of the plastic nozzle does not make the tip of the specially designed coaxial spinneret too thick relative to the Taylor cone. The sharper tip has another advantage in that it increases the charge density of the Taylor cone (point discharge phenomenon) so that the applied voltage does not need to be very high. Besides, the surface tension between the spinning solution and plastic nozzle is not strong enough to make the spinning solution spread up the plastic nozzle, so the electric-field force has not to overcome this surface tension, which further decreases the required voltage. As illustrated in the following Figure S1, two kinds of spinning solution have formed a coaxial structure before they flow to the tip of the plastic nozzle, and the Taylor cone remains in this coaxial structure. This illustrates how the structure of the final products reflects the structure of the spinning solutions in the lower part of the spinneret and the Taylor cone.