The Quantitative Nanomechanical Mapping of Starch/Kaolin Film Surfaces by Peak Force AFM

Abstract

Starch films modified with additives are materials increasingly being used in the production of packaging. These types of biopolymers can, to a considerable degree, replace plastic, contributing to the reduction in both production and waste management costs. However, they should be characterised by specific mechanical and surface parameters which determine their application. In the presented work, the PeakForce Quantitative Nanomechanics Mapping (PFQNM) method was applied to analyse a starch-based biopolymer modified with two different kaolin clay contents (5% and 10%). The technique used facilitates the assessment of the correlation of Atomic Force Microscope AFM height parameters with nanomechanical ones which provide the definitions of mutual interactions and allow the possibility to analyse materials in respect of various details. The investigated material was mapped in the Derjaguin–Muller–Toporov (DMT) modulus, adhesion and height domains. The results obtained indicated the impact of additives on the determined parameters. Increases in the DMT modulus and the adhesion force, along with the kaolin content, were observed. The enhancement of starch films with kaolin clay also induced growth in the surface roughness parameters.

Physical-Mechanical Behavior and Water-Barrier Properties of Biopolymers-Clay Nanocomposites

“…In this sense, it has been observed that some nano-sized additives added at low concentrations can generate significant improvements in the mechanical, thermal, optical, and physicochemical properties of the materials compared to the pure biopolymer, all this without compromising their biodegradability. The use of reinforcing materials with nanometric particle sizes favors a more homogeneous dispersion of these, increasing the specific surface of reinforcements such as nano cellulose and nanoclays; these materials also exhibit improved thermal, mechanical, and barrier properties when reinforcing concentrations used are lower (1-5% by volume) than when using micrometer size or larger reinforcements [9][10][11][12][13].…”

Microscopic Characterization of Poly(Sulfur Nitride)

“…In order to understand the surface morphology of SN x crystals in nm scale, AFM with various modes such as PeakForce Quantitative Nanomechanics (PF‐QNM) and standard tapping has been performed. [ 27–32 ] Figure shows AFM height images taken in PF‐QNM mode in two different sizes. The images depict the fibrillar nature of the SN x crystal with various fiber diameters in the range of about 50 to 100 nm.…”

Physical Properties of Starch/Powdered Activated Carbon Composite Films

“…A digital resolution of 512 px × 512 px and a scanning rate of 0.5 Hz were used, and the z-range was set at 300 nm. The Young's modulus was determined by fitting a linearized Derjaguin-Muller-Toporov (DMT) model to the contact part of the retraction curve [24,25]. Additionally, the adhesion force, identified by the attraction between the AFM tip and the sample surface, was determined.…”