Effect of capillary condensation on friction force and adhesion

• Friction force measurements have been conducted with a colloid probe on mica and silica (both hydrophilic and hydrophobised) after long (24 hour) exposure to high humidity air. Adhesion and friction measurements have also been performed on cellulose substrates. The long exposure to high humidity led to a large hysteresis between loading and unloading in the friction measurements with separation occurring at large negative applied loads. The large hysteresis in the friction-load relationship is attributed to a contact area hysteresis of the capillary condensate which built up during loading and did not evaporate during the unloading regime. The magnitude of the friction force varied dramatically between substrates and was lowest on the mica substrate and highest on the hydrophilic silica substrate with the hydrophobised silica and cellulose being intermediate. The adhesion due to capillary forces on cellulose was small compared to that on the other substrates, due to the greater roughness of these surfaces.

Subject headings

NATURVETENSKAP  -- Kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences (hsv//eng)

Keyword

Friction

capillary condensation

cellulose

mica

silica

atomic force microscopy

AFM

surface force

adhesion

paper

humidity

colloid probe

nanotribology.

Chemistry

Publication and Content Type

ref (subject category)

art (subject category)