Highly hydrophilic cotton fabrics were rendered superhydrophobic via electrostatic layer-by-layer
assembly of polyelectrolyte/silica nanoparticle multilayers on cotton fibers, followed with a fluoroalkylsilane
treatment. The surface morphology of the silica nanoparticle-coated fibers, which results in the
variety of the hydrophobicity, can be tailored by controlling the multilayer number. Although with the
static contact angle larger than 150◦, in the case of 1 or 3 multilayers, the fabrics showed sticky property
with a high contact angle hysteresis (>45◦). For the cotton fabrics assembled with 5 multilayers or more,
slippery superhydrophobicity with a contact angle hysteresis lower than 10◦ was achieved. The buoyancy
of the superhydrophobic fabric was examined by using a miniature boat made with the fabric. The superhydrophobic
fabric boat exhibited a remarkable loading capacity; for a boat with a volume of 8.0cm3, the
maximum loading was 11.6 or 12.2 g when the boat weight is included. Moreover, the superhydrophobic
cotton fabric showed a reasonable durability to withstand at least 30 machine washing cycles.