Nanoscale viscoelasticity characterization of engineered organometallic nanocomposite thin films for biomedical applications

This work is focused on nanoscale viscoelastic properties characterization of gold nanoparticles (AuNPs) rein-forced chitosan nanocomposites using nanoindentation. Chitosan nanocomposite films reinforced with gold nanoparticles concentration (w/v) up to 0.25 mg/ml in chitosan were prepared via a solution evaporation technique. Creep and stress relaxation responses were modeled using the generalized Voigt model and the generalized Maxwell model, respectively. Nanoindentation experimental data were analyzed using these models to obtain model constants. Both displacement-and load-controlled ramp functions were used to indent the samples with a 100 mu m conospherical indenter tip. The moduli increased with an increase in AuNPs concen-tration in chitosan. The plasticity index increased with an increase in AuNPs concentration indicating that the deformation became more plastic with an increase in the filler weight fraction. The results also show the time -dependent viscous response of the nanocomposite is mainly governed by the response of the matrix because the characteristic time scales of the nanocomposite films are independent of the AuNPs concentration.

Automated summary

This study focuses on the characterization of nanoscale viscoelastic properties of gold nanoparticle-reinforced chitosan nanocomposites using nanoindentation. The results show that the modulus and plasticity index of the nanocomposites increase with an increase in the concentration of gold nanoparticles. Moreover, the time-dependent viscous response of the nanocomposites is mainly governed by the response of the matrix.