Microstructured films such as brightness enhancing films, polymerizable resin compositions comprising an organic component and surface modified nanoparticles, and surface modified nanoparticles are described. The microstructured film has a polymerized structure comprising the reaction product of the polymerizable resin composition (e.g. having a refractive index of at least 1.58). The cured nanocomposite (e.g. structure) can exhibit improved crack resistance. In some embodiments, the flexibility is expressed in terms of a cylindrical mandrel bend test property (e.g. a mandrel size to failure of less than 6 mm or a mandrel size to failure according to the equation D=1000(T/0.025−T) wherein T is the thickness in millimeters of a (e.g. preformed base layer). In other embodiments, the flexibility is expressed in terms of a tensile and elongation property (e.g. a tensile strength at break of at least 25 MPa and an elongation at break of at least 1.75%).