2026 Student Poster Award - 3rd Place

Extensional rheology of CNT/redox-active polymer inks for critical element recovery

Haoqun Zhao | University of Minnesota
Jackson Cleveland | University of Minnesota
Michelle Calabrese, PhD | University Of Minnesota

Abstract

Redox-active polymers are promising electrode materials for critical element recovery due to their excellent ability to selectively target critical elements during electrosorption. However, processing and scaling of the redox-active polymer solution-based electronic inks are hindered due to the limited understanding of the ink quality control. In this work, we aim to explore the correlation between ink quality and extensional rheology, which is highly involved in spraying and inkjet printing. Polymer solutions with higher molecular weight and concentration usually lead to better device performance and durability. For the first time, ultra-high molecular weight (UHMW) redox-active polymer poly(TEMPO methacrylate) (PTMA) with number-average molecular weight (M_n) exceeding 2 MDa was accessed via free radical polymerization (FRP). However, these high molecular weight polymers undergo significant extensional stresses during coating processes which complicates the processibility. To better control the ink quality and extensional rheology of these inks, understanding the extensional behavior of the inks is essential. Due to the low-surface tension, low-viscosity of the organic solvents required to dissolve the redox-active polymers, dripping-onto-substrate (DoS) extensional rheometry is used to characterize the extensional behavior of the inks via capillary thinning. With a custom-built evaporation control chamber, DoS can accurately capture the extensional behavior of redox-active polymers in volatile solvents. By varying polymer molecular weight, concentration, and CNT dispersion quality, a fundamental understanding of how these parameters affect the processability of electronic inks can help optimize the ink formulation for critical element recovery.

3^rd Place, 97^th Annual Meeting, Oct 2026, Boston