AFM analysis of the surface morphology, structure, and mechanical properties of methylcellulose mixtures with colloidal silver dispersions

Abstract

The surface morphology, structure, mechanical properties, and physical transition temperatures of film compositions between methylcellulose (MC) and colloidal silver dispersions (CSDs) stabilized by poly-N-vinylpyrrolidone (PVP) are studied via atomic-force microscopy (AFM), X-ray diffraction and thermomechanical analyses, and mechanical tests. It is established that composite films exhibit the characteristic granular (nanodomain) surface morphology. When the CSD content in the compositions increases, the degree of ordering of MC macromolecules enhances, grain sizes decrease from ∼75 to ∼60 nm (at 3 and 20 wt % of the CSD, respectively), and the film surface relief becomes smoother. For example, the surface roughness of composite films is three times less than that of the initial MC film. In other words, owing to CSD introduction, film compositions are structurized at the nanolevel. In this case, Young’s modulus and the yield stress of composite films increase successively. High-temperature heating increases the average nanodomain size to 120–180 nm (for mixtures with 20 wt % of the CSD) and stimulates the local ordering of MC macromolecular fragments with sizes of ∼3–5 nm.