Colloidal phase behavior of high aspect ratio clay nanotubes in symmetric and asymmetric electrolytes

05 February 2024, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


Hypothesis: Imogolite nanotubes (INTs) are anisometric particles with nanometric diameters, as carbon nanotubes. But unlike the latter, the specific structure of imogolite nanotubes gives appreciable properties, such as monodispersity in diameter. Aluminogermanate double-walled INTs (Ge-DWINTs) are obtained with variable aspect ratios by controlling the synthesis conditions. It thus appears as an interesting model system to investigate how aspect ratio and ionic valence influence the colloidal behavior of highly anisometric 1D objects. Experiments: The nanotubes were synthesized by a 5 or 20 days hydrothermal treatment to modify the aspect ratio while the electrostatic interactions was investigated by comparing the colloidal stability in symmetric and asymmetric electrolytes. The phase behavior and their related microstructure were determined by optical observations and small-angle X-ray scattering measurements, coupled with interparticle distance modelling. Findings: We evidenced that colloidal suspensions of Ge-DWINTs prepared in NaCl are guided by repulsive double layer forces, undergoing different liquid crystal phase transitions before stiffen into a glass-like state. We found that the microstructure can be rationalized by taking into account the anisometric nature of the particles. By contrast, dispersions prepared with asymmetric electrolytes are governed by strong attractive forces and thus form space-filling gels containing large nanotubes aggregates.


columnar phase
phase diagram


Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.