Control method of heat capillary flow in liquid drop

Abstract

The invention relates to a control method of a heat capillary flow in a liquid drop in the field of an MEMS (Micro Electro Mechanical System) technique. The method provided by the invention comprises the following steps: machining a miniature heater on a substrate by utilizing the MEMS technique, wherein the dimension of the miniature heater is in a micrometer level and the area partially covered by a heating filament is less than that of the contact surface of the liquid drop with the substrate; then placing the liquid drop at the upper part of the miniature heater and applying voltages at the two ends of the miniature heater; enabling the heating filament of the miniature heater to generate heat and partially heats the bottom of the liquid drop; and generating a temperature gradient in the liquid drop, thereby causing the heat capillary flow flowing of the fluid in the liquid drop and controlling the heat capillary flow in the liquid drop. The method provided by the invention can be used for rapidly and effectively adjusting the temperature of the miniature heater to control the temperature distribution of the liquid drop, thereby controlling the heat capillary flow in the liquid drop and enhancing the controllable range of the heat capillary flow.

Description

technical field [0001] The invention relates to a method in the technical field of micro-electromechanical systems, in particular to a method for controlling thermal capillary flow inside a droplet. Background technique [0002] After the droplets containing solutes or particles are evaporated to dryness, the solutes or particles will be deposited on the surface of the fixation where the droplets are located, forming a certain deposition pattern. In the early 1990s, Deegan et al. found that when the liquid droplets fixed on the plate were heated at the bottom, the thermal capillary flow inside the liquid droplets was the main reason for the formation of ring-shaped deposition patterns after the liquid droplets evaporated, which also explained The famous "coffee ring" phenomenon. The evaporative deposition technology of droplets has many important applications in the fields of biomedicine and materials, such as DNA / RNA sequence analysis, drug delivery, and the manufacture of...

AI Technical Summary

Problems solved by technology

However, in the plate-based heating method, the contact surface between the droplet and the plate is heated as a whole, and the size of the droplet in practical applications is usually in the order of millimeters and microns. , the droplet temperature difference is not obvious, and the temperature gradient of the droplet is very small, so the thermal capillary flow generated inside the droplet is also very weak, which means that the controllable range of the thermal capillary flow inside the droplet is not wide by means of plate heating. The accuracy is not high

At the same time, because the heating method of the flat plate needs to maintain a stable temperature of the entire substrate, the temperature response time will be longer and the adjustment process will be more complicated.

Images