Piezoelectric materials (alpha-quartz, lead zirconate titanate) acting as sensors or actuators are most often referred to as "smart" materials. Lately thermoelectrics, multiferroics, magnetocaloric materials, giant magnetoresistance materials, magnetorheological, electrorheological fluids, shape memory materials (Nitinol, etc. .), thermo- and photosensitive polymers have been added to this class. Polymer gels that can change their volume (collapse of polymer gels) by more than a hundred of times with a small change in external conditions (temperature, solvent composition, pH) are also considered smart materials. Various polymer coatings that considerably change their conductive, optical and other properties when sorbing certain substances are used in sensor devices for environmental monitoring, in particular, to determine concentrations of toxic substances.

Not all smart materials are nanomaterials , but they are often used in nanotechnological applications. Thus, ferroelectric (piezoelectric) materials are used to build precise positioning devices (in particular, for scanning probe microscopy), and magnetorheological fluids use highly dispersed magnetic particles (nanoparticles). A number of nano-devices are based on piezoelectric materials (nanobalance, one-dimensional nanostructures of barium titanate or zinc oxide are used for power generation, etc.).