Polymer and polymer-clay nanocomposite laminates were prepared as transparent thermal actuators with possible uses in automatic aeration and ventilation or as thermal switches. Low levels of smectite clay addition reduced the thermal expansion coefficient of poly(methyl methacrylate) (PMMA) but retained optical clarity and reduced water absorption. X-ray diffraction and transmission electron microscopy were used to confirm the formation of PMMA-clay nanocomposites, and dynamic mechanical analysis was used to measure the coefficients of thermal expansion. The experimental values of the radius of curvature of the laminates from cantilever bending tests were in good agreement with the theoretical predictions for composite bars with only 4 wt % (nominally 1.3 vol %) mineral reinforcement. (C) 2008 Wiley Periodicals, Inc.