Facile measurement of polymer film thickness ranging from nanometer to micrometer scale using atomic force microscopy

As many properties of polymer thin films critically depend on their thickness, a convenient and cost-effective method for precise measurement of film thickness in a wide range is highly desirable. Here, we present a method which enables polymer film thickness, ranging from nanometer to micrometer scale, to be facilely determined by measuring the height of an artificially created film step on smooth substrates with atomic force microscopy (AFM). Three polymeric films (polystyrene, poly(methylmethacrylate) and poly(styrene-ethylene/butylene-styrene) films), spin-coated on either mica or quartz substrate with thickness ranging from 5.7 nm to 4.4 mu m, were employed to demonstrate the procedure and feasibility of our method. The proposed method is particularly suitable for thicker polymer films, thus complementing the traditional AFM 'tip-scratch' method which is generally limited to polymer films of no more than 100 nm thickness. Copyright (C) 2010 John Wiley & Sons, Ltd.