A novel process to produce a nanochannel comprised of a void in a polymer matrix is reported. The processing involves a selective degradation of one of the bicontinuous microdomain phases of microphase-separated block copolymers to create a continuous, tortuous hole having a diameter of nanometer scale (nanochannel) and plating of the surfaces with nickel metal. The nanochannel and the metal plating were confirmed by the transmission and scanning electron microscopies.