Lateral and Normal Forces in Polymer-Mediated Interaction of Alumina Surfaces

Polymer‐mediated interaction forces between an α‐alumina particle and c‐sapphire surfaces in methylcellulose solutions were measured by the atomic force microscope colloid probe technique. The effect of water soluble methylcellulose on normal and lateral surface forces was probed to understand the binding action of methylcellulose polymers. Methylcellulose bridgings up to ~300 nm in length have been measured. However, pretreatment of surfaces with NH4+ salt of poly(acrylic acid) resulted in fewer bridging events, probably due to preferential adsorption. The presence of methylcellulose bridging in friction loops was also measured in the form of superimposed spikes.