Evidence by X-ray scattering of defects in the lamellar stacking of the SmA phase of a side-chain polymer

An X-ray diffraction pattern in the SmA phase of a mesomorphic side chain polymethacrylate displays some unusual diffuse lines in addition to the elements already described. We account for these lines by introducing some defects which disturb the lamellar order. Such defects may be the places where the polymer main chain hops from one layer to an adjacent one.