Controlling the Length of Conical Pores Etched in Ion-Tracked Poly(ethylene terephthalate) Membranes

An etching procedure that allows for reproducible control of the length of conically shaped pores etched into poly(ethylene terephthalate) (PET) membranes is developed. At the lower etch temperature used (20 degrees C), the length of the pore is found to be linearly related to etch time. At the higher etch temperature (30 degrees C) the etch rate is five times faster and the pores quickly propagate through the entire thickness of the PET membrane. Hence, the lower etch temperature is best for controlling the pore length. Pores etched at this temperature are used to prepare arrays of gold cones where the length of the cones is controlled from 1 to 10 mu m. The track-etch rates and the radial-etch rates at both of the etch temperatures used are also reported.