Structure of Composite Based on Polyheteroarylene Matrix and ZrO₂ Nanostars Investigated by Quantitative Nanomechanical Mapping.

It is known that structure of the interface between inorganic nanoparticles and polymers significantly influences properties of a polymer⁻inorganic composite. At the same time, amount of experimental researches on the structure and properties of material near the inorganic-polymer interface is low. In this work, we report for the first time the investigation of nanomechanical properties and maps of adhesion of material near the inorganic-polymer interface for the polyheteroarylene nanocomposites based on semi-crystalline poly[4,4'-bis (4″-aminophenoxy)diphenyl]imide 1,3-bis (3',4-dicarboxyphenoxy) benzene, modified by ZrO₂ nanostars. Experiments were conducted using quantitative nanomechanical mapping (QNM) mode of atomic force microscopy (AFM) at the surface areas where holes were formed after falling out of inorganic particles. It was found that adhesion of AFM cantilever to the polymer surface is higher inside the hole than outside. This can be attributed to the presence of polar groups near ZrO₂ nanoparticle. QNM measurements revealed that polymer matrix has increased rigidity in the vicinity of the nanoparticles. Influence of ZrO₂ nanoparticles on the structure and thermal properties of semi-crystalline polyheteroarylene matrix was studied with wide-angle X-ray scattering, scanning electron microscopy, and differential scanning calorimetry.