Nanoindentation of clay colloidosomes

Autor: G. Mallikarjunachari, Trivikram Nallamilli, Madivala G. Basavaraj, Parag Ravindran
Rok vydání: 2018
Předmět:
Zdroj: Colloids and Surfaces A: Physicochemical and Engineering Aspects. 550:167-175
ISSN: 0927-7757
DOI: 10.1016/j.colsurfa.2018.04.041
Popis: Colloidosomes which are hollow structures made of a thin shell of colloidal particles are gaining significant attention because of possible applications in a number of fields such as agriculture, pharmacy, and food technology. Using the nanoindentation technique, we investigate the mechanical response of clay colloidosomes fabricated by drying clay particle stabilized oil-in-water emulsions. These emulsions form due to the synergistic stabilization of decane/water emulsions by a mixture of kaolinite and non-ionic surfactant SPAN-80. The use of colloidosomes in technological application often calls for estimation of mechanical response. In this work, the effect of load magnitude, loading rate and the diameter of the colloidosomes on the mechanical response is investigated. The magnitude of peak load and the rate of loading are varied from 20 μN to 200 μN and 2.5 μN/sec to 50 μN/sec respectively. The colloidosomes with diameters in the 8 μm to 16 μm range are investigated. The colloidosomes are found to be mechanically robust (do not rupture) below 140 μN and disintegrate or break above this load magnitude. The rate of loading is found to influence the slope of the load-displacement curve and the creep behavior, i.e., for a given peak load, the depth of penetration and hold displacement increase with increase in the loading rate. The indentation modulus and indentation hardness of colloidosomes of different diameters are found to be in the range of0.5-3.0 GPa and 15–40 MPa respectively.
Databáze: OpenAIRE
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