Ultramicrostructure and microthermomechanics of biological IR detectors: Materials properties from a biomimetic perspective

Microstructural organization of the biological infrared (IR) receptors was studied to elucidate their materials properties useful for prospective biom imetic design of artificial IR sensors from organic/polymeric materials. Th e IR receptors in Melanophila acuminata beetles were studied with ultrahigh -resolution scanning probe microscopy (SPM) in a range of temperatures. By application of micromechanical mapping and thermal stage, we made attempts to reveal the micromechanical and thermomechanical properties of the cuticu lar apparatus of the LR sensillum. The main component of the cuticular appa ratus is an internal endocuticular sphere with a diameter of about 15-20 mu m. Highly ordered multilayered organization of the lamellated peripheral ma ntle of the sphere was confirmed and characterized. We observed that the in terlayer spacing of this microstructure varied along the circumference and decreased to 300 nm in the vertex of the sphere. We demonstrated that the m icrolayered structure is composed of nanolayers with very different microme chanical properties and thermal behaviors. Thermal expansion of the outer m antle was observed, and the local thermal expansion coefficient under given preparation conditions was estimated to be below 1.5 x 10(-4) grad(-1).