聚合物纳米材料.pptVIP

聚合物纳米材料 ——微流控芯片 Glass and silicon micro-machining Polymer molding and machining Polymer thermoforming injection molding/hot embossing (ii) Polymer ablation polymer micromachining/laser ablation (iii) Polymer casting Fabrication Angew. Chem. Int. Ed.2006, 45, 7336 – 7356 Polymer thermoforming Injection molding, commonly used for many plastic products, involves the high pressure injection of melted thermoplastic pellets into a heated mold. Even though experimental parameters must be optimized for each production run, injection molding offers a high-throughput fabrication option. However, because of the complexity and high initial cost of the molding equipment and masters, injection molding is rarely used for rapid prototyping. Hot embossing is a fabrication method which consists of pressing a heated silicon or metal mold against a thermoplastic sheet, such as PMMA or COC to form device features. Embossing is fast and less expensive than injection molding, but still requires dedicated press equipment, a robust mold, and suffers from a lack of convenient methods for strong bonding. Polymer ablation Material from a polymer block can be removed to form microstructures using direct write processes such as conventional mechanical drilling and sawing, laser machining, powder blasting, and dry film laminating. In particular, laser ablation is also an advantageous alternative for prototyping, being cost-accessible and enabling complex 3D-multilayer structures. For this method, a high powered pulsed laser is used to remove material from a sheet of thermoplastic, like PMM A, PC, PVC and others, either through a mask or directly on the substrate. The primary disadvantage of all these direct methods is their limited throughput, due to the inherent serial nature. These techniques also generate surface roughness on microchannels, reducing their overall optical efficiency, as well as debris that have to be removed from the device. Additionally, channels