Observation of hollow helical fibers of MCM-41

Helical MCM-41 hollow fiber with circular inner cavity, helical mesoporous channels and twisted hexagonal outer contour was observed for the first time. The hollow fiber wall is supposed to be composed of layers of helical meso-channels winding around the fiber axis. Furthermore, the helical pitches of these meso-channels may increase gradually depending on their winding radii, giving rise to zigzag fringes along the fiber axis in TEM micrographs. The growth of helical hollow fibers may start from a circular hollow fiber, and be followed by side growth of layers of helical meso-channels with varying pitches from inner side to outer side of the fiber.