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The simple and applicable models predicting the mechanical properties of halloysite nanotubes (HNT)-based samples are extremely limited despite the experimental characterizations. It is important to consider the HNT network and nearby interphase section in the models, because big and thin HNT produce the network after percolation onset reinforcing the samples. Additionally, Ji model as a multiphase equation does not reflect the networks of nanoparticles and interphase section for the modulus of samples above percolation onset. In this paper, Ji model is progressed for the modulus of polymer HNT system containing the networks of HNT and adjacent interphase zone. The moduli and volume portions of networked HNT and nearby interphase section are expressed by simple equations and meaningful factors. The outputs of the advanced model at numerous ranges of all factors are discussed and verified. Also, the calculations of the progressed model accurately follow the experimental values of numerous samples. The modulus of system improves by 350% at the smallest range of HNT radius (=25 nm) and the highest value of interphase depth (=35 nm), while thick HNT and thin interphase cause the slight reinforcing. The network modulus of 600 GPa and the interphase modulus of 100 GPa produce the maximum modulus improvement as 150%. Moreover, poor polymer media and large HNT are desirable for the modulus of samples, whereas a strong polymer medium and short HNT slightly improve the stiffness. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: Thin organic films of octadecyltrichlorosilane (OTS) and aminopropyltriethoxysilane (APTES) were deposited on oxidized Si(111) substrates and characterised using atomic force microscopy (AFM) and nanoindentation methods. Films derived from a novel alkylsilane, 4-[N,N-(2-pyridyl)aniline]triethoxysilane (NDTS), which has properties similar to related electroluminescent and fluorescent compounds, were also examined. This latter compound could be used to directly couple a fluorescent or electroluminescent centre to a semiconductor surface, with applications in microfluidics or other microelectronic-based sensors. AFM images showed that when OTS or APTES was deposited from ethanol solution onto the oxidized Si surface, an inhomogeneous film was formed, containing both smooth regions and polymerised particles of the alkylsilanes up to 200nm in diameter. Nanoindentation force/displacement curves could clearly distinguish these two regions of the film, and they showed quite different mechanical properties. When deposited from a solution of ethanol and CH2Cl2, OTS films were smooth and completely covered the surface. Discontinuities in the force/displacement curves, corresponding to a breakthrough by the indentor through the film into the substrate showed that these films were some 2nm in thickness. When OTS, APTES or NDTS were deposited from CH2Cl2 solution, similar discontinuities could be observed, and showed that the film thickness increased, and roughness decreased, as the concentration of alkylsilane in solution was decreased. The results are discussed in the context of using nanoindentation methods as a means of characterising organic thin films. [Copyright &y& Elsevier]