Long-range attractive forces extending from alumina nanofiber surface

Aluminum oxide-hydroxide nanofibers, 2 nm in diameter and approximately 250 nm long, are electroadhesively grafted onto glass microfibers, therefore forming a macroscopic assembly of alumina nanofibers on the second solid in highly organized matter. The assembly can be viewed as a straight cylinder with rough surface and charge density of approximately 0.08 C/m2. This creates a significant electric field with negligible screening (ka ≪ 1) in the region close to the surface of the assemblies. This field attracts nano- and micron-size particles from as far as 0.3 mm in less than a few seconds, many orders of magnitude greater than the conventional Derjaguin–Landau–Verwey–Overbeek theory that predicts only nanometer-scale effects arising from the presence of the surface. The strong electric field on the surface is then able to retain particles such as micron-size powdered activated carbon as well as much smaller particles such as fumed silica nanoparticles of 10–15 nm in diameter, viruses, atomically thick sheets of graphene oxide, latex spheres, RNA, DNA, proteins, and dyes.