Polymer Microfluidic Chip Mold Temperature Control Of Bonding And Bonding Study

In recent years, microfluidic chip has received increasing attention in the field of chemical and biological analysis by characteristics of rapidity, high effectiveness and low consumption. Polymers are less expensive and easier to manufacture in large quantities, which make up the shortcomings of quartz and glass. In addition, polymers have good electrochemical properties and biological compatibility, making them the best choice for microfluidic chip fabrication. The conditional fabricating method of microfluidic chip is ineffective, and manufacturing cycle of that is long, for molding technology and bonding technology are seperated. In this paper, bond-in-mold technology was introduced for the purpose of manufacturing chip in large quantities with low cost.Firstly, diffusion theory and adsorption theory were used for describing the process of bonding, then searching root causes of bonding were found from the view of surface tension and bonding energy, so feasibility of bond-in-mold technology was verified.Microchannel distortion in thermal bonding was studied by finite element software, and the results showed that distortion in the direction of height is quite large, on the contrary distortion in the direction of height is indistinctive. The distortion in the direction of height was growing with increasing bonding temperature and pressure, and bonding temperature had larger influence on it. When bonding temperature was higher than glass-transition temperature of material, distortion of microchannel was comparatively serious.Far-infrared ceramic heaters were chosen to heat surface of the chip, after analyzing requirements of bond-in-mold technology. The heating system for bond-in-mold and temperature control system with PID algorithm were designed and developed. The temperature heater was controlled for working under SV by setting parameters of PID. Experiments of heating bonding surface were carried out, then relationships between surface temperature and heating parameters were obtained.Bond-in-mold experiment was carried out after designing orthogonal experiment with injection and bonding mold of microfluidic chip. The effects of main factors on height of microchannel were analyzed by Range Method. Then optimal combination of bonding parameters were obtained taking chip feature and bonding strength into account.