AFM of amidine latex particles attachment on mica

The attachment of amidine latex particles with 290 nm diameter on mica surface in the presence of humic acid (HA) and/or Calcium ions (Ca2+) was investigated with atomic force microscopy. In the absence of both HA and Ca2+, adhesion of the colloidal particles onto the solid substrate increased with time as clusters formed and grew. The attachment occurred almost evenly across micaʹs surface. HA substances in the latex suspension significantly reduced the attachment of amidine latex particles onto the mica surface. In addition, most attached latex particles tended to aggregate so as to form some big clusters at very sparse spots in the presence of HA, therefore, exhibiting a selective style of attachment. The presence of Ca2+ greatly enhanced the attachment of amidine latex particles whether in the absence or in the presence of HA.