Photochemistry for Advanced Nanoengineering: Polymer Microtubes with Inner Walls Coated with Silver Nanoparticles

Micro-capillaries with an engineered hidden surface were produced via the self-rolling of polymer thin films whose surface was photochemically modified so as to coat it with silver nanoparticles. The polymer films consisted of a poly(4-vinyl pyridine) (P4VP) layer topcoated with a polystyrene layer. When immersed in acid water, they underwent self-rolling due to selective swelling of the poly(4-vinyl pyridine) layer. The generation of Ag nanoparticles at the inner structure of the 40 μm-wide capillaries was carried out by a photochemically initiated reduction process. It was confirmed by UV-VIS spectroscopy, transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX) analysis. The possibility of designing non-uniform distributions of silver particles at the inner surface of the tubes was also established. It consists of photopatterning the top of the film the polystyrene side prior to the swelling/selfrolling step. This approach provides new opportunities for the design of micro-compartments for micro-biological research and for micro-fluidics applications.