DIRECTED IONIC TRANSPORT IN POLY(IONIC LIQUID)-GRAFTED

NANOPARTICLES IN POLARIZABLE MEDIA

Polymer-based electrolytes address the critical challenge of creating high-performance, safe electrolytes for electrochemical devices by offering enhanced safety and mechanical stability compared to traditional liquid electrolytes; however, they often fall short in achieving comparable ionic conductivity. To address this limitation, this project introduced an innovative design strategy leveraging the self-assembly of polymer-grafted nanoparticles to form efficient ion-conducting pathways for improved ionic transport.

This project explored the ionic, hydrogen and ion-dipole interactions between polyelectrolyte-grafted chains and medium such as solvent or ionic liquid to mitigate the particle dispersion and structures. Particle dispersion and continuous percolated nanostructures are critical properties in electrolyte design and this project utilized the particle design strategy with PIL-grafted, PMMA-grafted and with their copolymer-grafted forms. Through the percolation and less studied factors such as grafted chain stretching and confinement are used to explain the high ion conductivity that supports the ladder-like ion hopping between PIL chains grafted around particles.

The project systematically investigated a series of interrelated systems-ranging from ionomers, polymer/ionic liquid mixtures and poly(ionic liquid) containing block copolymer-grafted particles. Our initial experiments on charged copolymer-grafted nanoparticles showed the importance of percolation of ion clusters for ion transport. To investigate the role of the interface between the non-conductive filler and polymer, we designed hybrid electrolytes based on single-ion conducting polymers grafted on nanoparticles. Poly(ionic liquid) (PIL)-grafted nanoparticles were synthesized for the first time, and PIL chain length and assembled structures were found to improve the ion conductivity compared to that of particle-free poly(ionic liquid) homopolymer. Finally, copolymers comprising a single-ion conducting domain (PIL) and poly(methyl methacrylate) (PMMA) were synthesized, integrating ion-dipole interactions between PMMA and the ionic liquid, along with coordinated anion transport facilitated by the polycations. The variations in the PIL block length, diblock sequence, and the incorporation of ionic liquid into the copolymer hybrids modulate the net repulsion between nanoparticles, resulting in conduction pathways with distinct morphologies. The highest molar conductivity was observed with well-dispersed copolymer grafted nanoparticles, where the PIL coronas established continuous pathways for ion transport. Moreover, the polarization and rearrangement of charged chains under applied electric fields demonstrated the potential of these hybrid electrolytes for applications in electroactive actuators, sensors and electrochemical devices.

One PhD student is completed his PhD dissertation on this project and another PhD student is partially supported and several undergraduate student researchers from Stevens and REU students from other universities participated in the project. Research results from the project were presented by the PI as invited talks at the 2022 APS March Meeting Polymer Physics Prize Session; University of Rhode Island in 2022; Stockholm University, Sweden in 2023; Queens College, CUNY, NY in 2023; Seton Hall, NJ in 2023; The 18^th Pacific Polymer Conference (PPC18), Puerto Vallarta, Mexico in 2023; ACS MARM, PMSE, Advancing and Designing Polymer Materials through Chemistry and Engineering Symposium, Pennsylvania State University, University Park in 2024; APS March Meeting, Anaheim, CA, Invited Session: Structure and Properties of Ionic Polymer Solutions and Electrolytes in 2025 and Oklahoma State University, Chemical Engineering Department in 2025. Graduate students also gave talks and poster presentations at the national APS March Meetings, ACS Meetings and GRS Ionic Liquids meetings.

Last Modified: 05/07/2025
Modified by: Pinar Akcora