Session: 20-17-01: Rising Stars of Mechanical Engineering

Paper Number: 172175

Multi-Scale Mechanical Behavior of Quantum Dot Nanocomposites: Towards Data-Driven Automatic Discovery of High-Performance Structures 

Thermosetting polymers, extensively used in aerospace, defense, electronics, and transportation industries, possess high thermal stability, structural rigidity, and chemical resistance. Despite their favorable properties, these materials face significant limitations due to inherent brittleness, restricting their effectiveness in structural applications that require toughness and energy absorption. Annually, over 65 million tons of thermosetting polymers are used globally, with a significant fraction in fiber-reinforced composites demanding high strength and stiffness. Enhancing toughness in these materials is critical to reduce weight, prevent catastrophic failures, and extend operational life, especially in high-performance applications.

Quantum dot (QD) nanoparticles, particularly two-dimensional (2D) quantum dots below 20 nm, present a promising avenue to simultaneously enhance strength and toughness in thermosetting polymers. Recent studies have demonstrated that QDs can significantly improve epoxy toughness, fracture work, and strength. However, the fundamental molecular-level mechanisms by which QDs enhance these mechanical properties remain unclear, posing a critical knowledge gap.

This gap is addressed by systematically investigating the multi-scale mechanical behavior of thermosetting polymer composites reinforced with ultra-small 2D quantum dots. The objective is to elucidate the molecular deformation mechanisms, load transfer dynamics, plastic deformation, debonding, and toughening mechanisms specific to quantum dot nanocomposites. The approach combines molecular dynamics (MD) simulations with advanced experimental techniques such as positron annihilation lifetime spectroscopy (PALS), in-situ Raman spectroscopy, and synchrotron X-ray characterization, alongside informatics-driven multi-scale modeling.

Preliminary molecular dynamics results reveal mechanical enhancements in epoxy composites reinforced with oxidized graphene quantum dots (GQDs). Specifically, hydroxyl-functionalized GQDs have been identified as highly effective, achieving an increase in stiffness by approximately 20 % and yield strength enhancements up to 60 % relative to neat epoxy systems. Structural analyses indicate these GQDs promote densely packed molecular configurations, effectively reducing free volume and enhancing mechanical performance through increased hydrogen bonding and π-π stacking interactions.

In addition to advancing the fundamental understanding of quantum dot nanocomposite mechanics, the present study contributes to the field by developing an innovative atomistic-level data-driven predictive framework leveraging machine learning. This transformative approach accelerates the identification and optimization of quantum dot formulations, streamlining the discovery process for next-generation high-performance materials. Our ongoing research aims to fully automate the enhancement of material properties, targeting advanced systems such as nanorobots, NEMS, MEMS, solar collectors, solar cells, and structural fiber composite batteries.

Complementing these scientific advancements, our educational component integrates modern and interactive strategies to prepare engineering students for technological innovation. Initiatives include the development of artificial intelligence (AI)-driven tutors, open-source virtual reality learning environments, and collaborative interdisciplinary projects specifically aimed at fostering creativity.

Presenting Author: Ozgur Keles University of North Carolina at Charlotte

Presenting Author Biography: Dr. Keles is an Associate Professor of Mechanical Engineering and Engineering Science at the University of North Carolina at Charlotte. He received his B.S. and M.S. degrees from the Department of Metallurgical and Materials Engineering at Middle East Technical University and his Ph.D. from the School of Materials Engineering at Purdue University. Following his doctorate, he joined the Illinois Institute of Technology as a research associate, investigating the reliability of ceramics and pharmaceutical materials. His current research interests include artificially intelligent automatic discovery of nanocomposites, nanoelectromechanical systems, and AI education, funded through NSF CAREER, NSF MRIs, the National Endowment for the Arts, and industrial partners. Dr. Keles is also a photographer and digital artist who uses aesthetically appealing images and computer visualizations to aid student learning and foster creativity among engineering students.

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