A structural comparison of halloysite nanotubes of different origin by Small-Angle Neutron Scattering (SANS) and electric birefringence

Giuseppe Cavallaro, Leonardo Chiappisi, Pooria Pasbakhsh, Michael Gradzielski, Giuseppe Lazzara

Research output: Chapter in Book/Report/Conference proceedingConference PaperOther

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The structure of halloysite nanotubes (Hal) from different mines was investigated by Small-Angle Neutron Scattering (SANS) and Electric Birefringence (EBR) experiments. The analysis of the SANS curves allowed us to correlate the sizes and polydispersity and the specific surfaces (obtained by a Porod analysis of the SANS data) of the nanotubes with their specific geological setting. Contrast matching measurements were performed on patch Hal (from Western Australia) in order to determine their experimental scattering length density for a more precise analysis. Further characterization of the mesoscopic structure of Hal was carried out by Electric Birefringence (EBR), which allowed to study the rotational mobility of Hal. From the obtained rotational diffusion coefficients of the different Hal we deduced their length via the Broersma theory, which compares well to TEM data. The analysis of both SANS and EBR data provided a bulk average information on the Hal structure in water, which, for instance, documented the markedly higher degree of well-definedness of the PT-Hal and the thinner tube walls present here. The attained systematic structural knowledge represents a step forward for the robust structural description of halloysites selected from four geological deposits and shows that Hal of different origin differ very markedly with respect to their mesoscopic structure.

Original languageEnglish
Title of host publication16th International Clay Conference (ICC)
Number of pages10
Publication statusPublished - Aug 2018
Event16th International Clay Conference (ICC) - Grenada, Spain
Duration: 16 Jul 201621 Jul 2016
Conference number: 16th

Publication series

NameApplied Clay Science
ISSN (Print)0169-1317


Conference16th International Clay Conference (ICC)
Abbreviated titleICC
Internet address


  • Electric Birefringence
  • Halloysite nanotubes
  • Patch halloysite
  • Small Angle Neutron Scattering

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