The invention relates to a solid body of plastic, glass, ceramic or metal which has at least partially a microstructured surface with rows oriented in a preferential direction of cross-sectionally trapezoidal or wedge-shaped ridges, wherein the ridges have minima and maxima in height (H) which lie in the range from 0 mm to 2 mm, and the minima and maxima follow one another periodically with amplitudes in the range from 0.005 to 20 mm, and the spacing of the rows of neighboring ridges in relation to one another is 0.002 mm to 5 mm, it being possible for the valleys between the rows to be planar, curved or tapered, and the cross-sectionally trapezoidal or wedge-shaped ridges have a wedge angle () in the range from 15 to 75.