Temperature-Controlled Molecular Bonding Hysteresis: Interphase Dynamics of a Nanoparticle-Modified Polymer Network

Area of Science:

• Materials Science
• Polymer Science
• Nanotechnology

Background:

• Epoxy-based polymers with core-shell rubber nanoparticles exhibit complex interfacial behavior.
• Understanding molecular bonding dynamics at these interfaces is crucial for advanced material design.

Purpose of the Study:

• To demonstrate and characterize temperature-induced molecular bonding hysteresis at nanoparticle-polymer interfaces.
• To investigate the relationship between electrical polarization, optical properties, and thermal stimuli.

Main Methods:

• Utilized core-shell rubber nanoparticles within a highly cross-linked epoxy-based polymer.
• Employed temperature-modulated optical refractometry (TMOR) to measure refractive index changes.
• Analyzed quasi-static and dynamic thermal expansion to understand hysteresis origins.

Main Results:

• Observed a hysteresis-like change in electrical bond polarization strength at the nanoparticle-polymer interface.
• Demonstrated controllable switching of dynamic bond behavior via temperature variation.
• Detected optical remanence through a refractive index hysteresis independent of temperature change.

Conclusions:

• The observed hysteresis is attributed to specific refractivity, not dipole number density.
• Temperature-induced molecular bonding hysteresis offers a new mechanism for tunable material properties.