Microfluidics is a highly interdisciplinary science which deals with the behavior, control and manipulation of fluids that are constrained to sub-milimeter scale. It incorporates the knowledge and technique intersecting physics, chemistry, mechanics, nanoscience and biotechnology, with practical applications to the design of systems in which small volumes of fluids will be used. Advances in it have been significantly enhanced by the development of simple, low cost fabrication techniques. Perhaps the most influential of these techniques is the use of poly (dimethylsiloxane) PDMS. In addition, PDMS-based functional materials and PDMS with modified surface property contribute much to the broad applications of PDMS in microfluidics....[ Read more ]

Microfluidics is a highly interdisciplinary science which deals with the behavior, control and manipulation of fluids that are constrained to sub-milimeter scale. It incorporates the knowledge and technique intersecting physics, chemistry, mechanics, nanoscience and biotechnology, with practical applications to the design of systems in which small volumes of fluids will be used. Advances in it have been significantly enhanced by the development of simple, low cost fabrication techniques. Perhaps the most influential of these techniques is the use of poly (dimethylsiloxane) PDMS. In addition, PDMS-based functional materials and PDMS with modified surface property contribute much to the broad applications of PDMS in microfluidics.

In this thesis, we first determined the critical droplet volume for spontaneous capillary wrapping of PDMS, which was of great significance in microfabrication of 3D structures. Then we fabricated universal logic gate microchip from PDMS as molding microchannels from structured masters, and embedded PDMS-based conducting composite as electrodes in it. Based on this, hybrid divider was achieved which employed droplet as a hybrid electronic component for actuator control and realized automatic droplet logic manipulation. A new method for PDMS surface modification was proposed, which could bring about selective modification easily and efficiently. Lastly, we successfully used PDMS-based magnetic composite to control the drug release profile and achieved digitized microfluidic drug delivery. Such composite was named as CI-PDMS, which integrated both the magnetic response character of CI particles and good mechancial properties of PDMS. The main meaning of this work is to explore the further application of PDMS or PDMS-based functional materials in microfluidics and biomicrofluidics.