Current (and future) engineering materials demand for multi-responsive performance

It is already more than 30 years since the enouncement of the era of Smart Materials .The new 'promising land' concentrated the interest of researchers from different fields (i.e.metals, ceramics, polymers, composites) because of stimuli-responsive materials, such as shape memory alloys, electro/magneto-rheological fluids, and piezo/ ferro-electric materials, which were known and under study by that time.As smart materials are referred structures which integrate actuating and sensing elements into a composite system (https://doi.org/ 10.3144/expresspolymlett. 2011.100).Materials of this class are able to vary some of their properties (natural vibration frequency, damping coefficient, shape, polarization etc.) in response to an external stimulus (https://doi.org/10.1023/A:1004869613018).Adjustable properties, self-tuning behaviour, and biomimetic approach became the key factors for developing of 'smart', 'intelligent', or 'adaptive' materials.Besides the term used for describing this type of materials, they should be able to replace machines/devices, by caring out tasks not as a consequence of signals or impulses passed from one component to another, but as result of their intrinsic properties.Although, significant progress has been conducted in the field (i.e., shape controlling or morphing materials, systems with tunable viscosity, electrical switches with no movable parts, self-healing materials etc.), insurmountable obstacles for achieving complete 'smartness' exist, since machines/devices/materials do not grow, metabolize, or self-propagate by their own means.Typically, the adjective 'smart' is assigned to animals/biological systems.