Polyeurathane and gel-bound PBX systems are studied using atomic force microscopy (AFM). Comparative images for the pure explosive crystals and the binders are taken and compared. The images reveal a complex structure for the polyeurathane-bound system in which there is a surprising diversity of features. The gel system appears to be simpler appearing as a two-phase system. In both cases, however, the stiffening effect of the crystals on the binder is emphasised. (C 2002 Elsevier Science B.V. All rights reserved.