Experiment and simulation study on the demolding process of injection-molded microfluidic chips for heavy metal detection

The demolding process of polymer microfluidic chips fabricated by injection molding will directly affect their performance. In this study, experiments and molecular dynamics (MD) simulation were combined to investigate the demolding quality of the microstructures for heavy metal detection on microfluidic chips. The experimental results showed that the microfluidic chips could be completely molded, but the edges of the microstructures were stretched to a certain extent and the bottom of the microchannel was depressed. The simulation results showed that the interfacial adhesion between the polymer molecular chains and the mold insert was the main factor affecting the demolding resistance. Furthermore, the change of the gyration radius was used to characterize the deformations of polymer molecular chains during the demolding process. The MD method can effectively explain the internal mechanisms of interfacial interactions that cause the demolding deformations of polymer structures from the molecular/atomic scale.