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.