GAS-ASSISTED LOW TEMPERATURE BONDING OF POLYMERIC MICRO/NANOSTRUCTURES

摘要

Polymer-based biomedical microanodevices containing environmentally sensitive biomolecules are attracting increased interest. A critical requirement is the ability to assemble these devices at low temperatures in order to minimize denaturization. Studies of polymer thin films revealed that the properties at the polymer surface differed from those in the bulk. It was found that glass transition temperatures (T_g) at the polymer-air surface was substantially lower than the bulk T_g and increased toward the bulk value with depth from the surface. Subcritical CO_2 could enhance the chain mobility and greatly depress T_g near the surface. Benefiting from this, we successfully demonstrated low temperature bonding of polymeric microanostructures. The original microanostructures are perfectly preserved after bonding.