TRANSPORT IN HYDROPHOBIZED MONTMORILLONITE THIN-FILMS

SWy-1 montmorillonite clay treated with short-chain and long-chain ali phatic, aromatic, and aliphatic-aromatic quaternary ammonium compounds (QAC) was investigated. The transport properties of the electroactive probes Fe(CN)(6)(3-), Ru(NH3)(6)(3+), and p-benzoquinone have been st udied by cyclic voltammetric techniques. Coverage at 3.7% and lower of the cation exchange capacity (CEC) of the clay had little impact on t he hydrophobic behavior of the film or on the retention of the probe m olecule. At 37% coverage, all of the short-chain QAC behaved similarly and inhibited expansion of the clay-reducing transport of the anion, but had little impact on the cation or neutral aromatic. The long-chai n QAC all behaved similarly and disrupted the clay structure such that the water-soluble ionic probes travel in pinholes while the aromatic is retained in hydrophobic domains.