Inhibiting effect of dopamine adsorption and polymerization on hydrated swelling of montmorillonite

This paper aims at evaluating the inhibition performance of dopamine (DA) on hydrated swelling of montmorillonite (MMT) and exploring the inhibitive mechanism. The inhibition performance of DA was evaluated through the combination of linear swelling and mud making tests, and compared with three commonly used inhibitors in the field. The results show that DA performs extremely well on inhibiting the MMT swelling, within a broad temperature range even at 200 °C. Based on a combined use of FT-IR, XPS, XRD, zeta potential and TEM analysis, the probable inhibition mechanism was determined due to the identification of the structure of polydopamine (pDA) polymerized in the MMT interlayer. The results indicate that the forming of interlayered pDA that composed of bilayer planer 5, 6-dihydroxyindole (DHI) oligomers is primarily responsible for the excellent inhibition ability of DA. In addition to this, the collapse of MMT colloidal particle diffuse double layers due to the adsorption of positive charged DA monomers also contributed considerably to the inhibition effect on hydrated swelling.

Graphical abstractThe adsorption and polymerization of dopamine in the interlayer inhibit the hydrated swelling of montmorillonite.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Dopamine exhibits strong inhibiting effect on hydrated swelling of montmorillonite. ► The unique structure of interlayer polydopamine accounts for the high inhibition. ► The interlayered polydopamine has a structure of bilayer planer oligomers. ► The adsorption of positive charged dopamine plays an important role on inhibition.