Within this study the potential of thermotropic layers to prevent overheating of an all-polymeric solar collector is evaluated by theoretical modeling. The investigations show that collector stagnation temperatures can be reduced to temperatures between 80 and 90 degrees C by using thermotropic layers either in the glazing or on the absorber. For overheating protection to a maximum temperature of 80-90 degrees C a residual solar transmittance of the thermotropic layer below 0.25 in the opaque state (> 0.85 in clear state) is effectual. The required switching temperature is dependent on the collector configuration. (c) 2007 Elsevier B.V. All rights reserved.