Tuning Interparticle Contacts and Transport Properties of Maghemite–Thermoset Nanocomposites by Applying Oscillating Magnetic Fields

Abstract

Conductive nanofillers, if integrated in an organized manner, can improve the transport properties of polymer matrices without compromising on their light weight. However, the relationship between the particle assemblies and transport properties of such nanocomposites, especially the competing effects of connected nanofiller pathways compared to resistances at interparticle contacts, has not been quantitatively studied. In this work, with the model nanocomposite of maghemite nanoparticles in epoxy, a novel fabrication method has been demonstrated to align nanofillers and control the interparticle contact amount within such a nanofiller assembly, using nanoparticle surface functionalization and oscillating magnetic field application. The nanofiller assembly cross-sectional areas were measured by processing micro-CT images and compared with the measured electrical and thermal properties of the nanocomposites. In terms of thermal transport, when the nanofiller assembly cross-sectional area was small, the dominance of conductivity pathways was observed up to ∼4.7 vol %, while interfacial thermal resistance began to dominate when the nanofiller assembly cross-sectional area became larger than 2700 μm2.

Development and Perspectives of Thermal Conductive Polymer Composites

“…Therefore, improving the interface compatibility between the two is a common means to reduce phonon scattering. In recent decades, researchers have used different methods to treat the surface of fillers to improve the interfacial adhesion between fillers and polymer matrix [ 13 , 104 , 105 , 106 , 107 , 108 , 109 , 110 , 111 , 112 , 113 ]. Commonly used modifiers include surfactants, coupling agents, functional polymers, and inorganic coatings [ 81 ].…”

Tuning the dimensional order in self-assembled magnetic nanostructures: theory, simulations, and experiments

“…Bottom-up self-assembly has emerged as a powerful strategy for organizing nanoscale building blocks into well-ordered supercrystals or superstructures. [1][2][3] These self-assembled materials possess remarkable collective properties due to the synergistic interactions among individual building blocks, leading to enhanced optical, 4 plasmonic, 5 catalytic, 6 electronic, 7 magnetic, [8][9][10][11] thermal, 12 and mechanical 13 characteristics. In particular, the self-assembly of magnetic nano-particles (MNPs) offers an intriguing avenue to harness magnetism as an additional degree of freedom in magneto-composite fabrication.…”

Homogenizing Blends of Cross-linked Polymers by Interfacial Exchange Reactions

“…Thermosetting polymers have been widely used in numerous applications ranging from commodities to high-end manufacturing fields because of their excellent dimensional stability and thermal and chemical resistance properties. − However, it also brings an end-of-life issue where traditional thermosets cannot be reprocessed or recycled after use due to their cross-linked networks, leading to serious resource waste and environmental pollution. These problems have aroused extensive concern worldwide, especially in the context of fossil resource depletion and excessive carbon emissions. − …”