Young's and shear moduli of Fe3+-doped chrysotile nanoscrolls probed by atomic force microscopy

Here, we investigate an influence of Fe3+ content on the mechanical behavior of Mg3Si2O5(OH)4 synthetic phyllosilicate nanoscrolls with chrysotile structure during the bending tests carried out by atomic force microscopy. The developed approach to the microscopy data treatment allowed us to consider fixing conditions, elasticity of the foundation, and shear strain contributions to the observed Young's modulus value. Doping by 6 at% of Fe3+ decreased the Young's modulus from 238 down to 150 GPa. The applied density -functional theory calculations confirmed the same trend for the most energy preferable types of Mg2+ and Si4+ substitutons by Fe3+. Despite major part of the experimental data has been satisfactory explained within the shear strain contribution assumption, doping by Fe3+ gives rise to nanoscrolls with anomalous Young's modulus value (600 +/- 200 GPa). Potential reasons of the effect are considered.