Polymer nanonozzle arrays are fabricated using a sacrificial template imprinting (STI) approach (see Figure). Polymer sacrificial templates, which can be easily removed after molding, are used in place of rigid masters. This approach avoids generation of structural damage or defects during demolding. The diameter of the sharp end of each nanonozzle is as small as 80 nm, and can be further reduced by silica synthesis on the inner channel surface.