(2bq) From Molecular Design to Macroscopic Properties: Interfacing Principles of Materials Chemistry, Molecular Self-Assembly, and Polymer Science for Sustainability

My research emphasizes small molecule and macromolecular synthesis, nanoscale dynamics-macroscopic property relationships, and bottom-up fabrication to formulate materials for applications in sustainability spanning efficiently remediating contaminated water to chemically recycling bio-derivable polymers. I am excited to use this background to interface historically distinct areas of soft matter research to develop new fundamental understandings and methods for control of molecular-scale dynamics and interfacial behavior. In turn, I will use these discoveries to design impactful new materials for applications in sustainability. Specifically, I will (1) investigate the interplay between material, water, and contaminant nanoscale dynamics towards developing effective water treatment materials for challenging-to-remove pollutants; (2) explore the deconstruction of unusual biobased feedstocks to small molecules and the subsequent valorization of these compounds to molecular and polymeric systems; and (3) harness molecular self-assembly to pattern organization in polymeric materials for conductive and catalytic applications including carbon capture.

Research Experience

Molecular self-assembly offers a powerful bottom-up approach to producing nanostructures with high surface areas, tunable surface chemistries, and pristine internal order. Conventionally, the dynamic nature of these systems has constrained their use to specific cases in aqueous environments. As an NSF Graduate Research Fellow, Martin Fellow for Sustainability, and Hugh Hampton Young Fellow, I designed molecular assemblies constructed from small molecule aramid amphiphiles (AAs) to overcome these limitations. AAs incorporate a Kevlar-inspired domain to impart strong, cohesive intermolecular interactions between molecules, which self-assemble into nanoribbons with suppressed dynamic mobility and mechanical properties rivaling silk (Christoff-Tempesta, et.al., Nature Nano., 2021). I harnessed this stability to expand the application space of small-molecule assemblies to, among others, performing post-assembly surface reactions (Cho, Christoff-Tempesta, et. al., Nature Comm., 2021), stabilizing unusual metastable nanostructures (Christoff-Tempesta, et.al., Nano Letters, 2021), and extending molecular assemblies to the solid-state. Finally, I leveraged surface areas near 200 m²/g and control over interfacial and conformational dynamics to design AA nanostructures that can treat thousands of liters of 50 ppb lead-contaminated water with single milligrams of material (Christoff-Tempesta, et. al., Environ. Sci.: Nano, 2021; Christoff-Tempesta, et. al., under revision). Employing molecular design to incorporate durable interactions into supramolecular polymers offers a route to surmount limitations of conventional assemblies, enabling customizable nanomaterials for demanding applications.

Designing polymers using compounds obtainable through the deconstruction of biomass from industrial waste streams offers a sustainable pathway to replace petrochemical-based monomers. However, the responsible end-of-life management of bio-derivable, non-biodegradable polymers remains an outstanding challenge. In my postdoc, I have expanded my experimental background in macromolecular chemistry by investigating the use of lignin-derivable compounds to produce high-performance polymer systems and the chemical recycling of these systems. Recently, I reported the quantitative thermal depolymerization of lignin-derivable polymethacrylates to their constituent monomers (Christoff-Tempesta et. al., submitted). Interrogating the impact of reaction atmosphere and polymer chemistry on depolymerization kinetics and thermodynamics enabled efficient bulk depolymerization and consequent demonstration of upcycling over multiple life cycles. This work in macromolecular chemistry and sustainable design complements my previous research in small molecule synthesis and bottom-up materials fabrication to achieve my future research goals.

For a full list of published work: https://tinyurl.com/tychristoff

Teaching Interests

As a graduate student at MIT, I developed two classes alongside faculty members – “The Future: Global Challenges and Questions” (SP.246) and “People and the Planet: Environmental Governance and Science” (12.387J) – with an emphasis on encouraging a high level of student involvement to maximize impact. These experiences with active learning and sustainable thinking informed my development of a new class, “Experiential Sustainability” (1.005), which I piloted and taught at MIT in 2021. Experiential Sustainability bridged the divide between classroom learning and ‘the real world’ to engage engineering students in sustainable thinking from diverse perspectives. I look forward to harnessing active learning to teach a wide range of courses spanning undergraduate and graduate levels, including polymer chemistry, polymer physics, polymer processing, soft matter characterization, and core thermodynamics and kinetics courses. I am also excited to develop new classes, such as a food-inspired soft matter class to engage early undergraduate students in STEM and graduate-level soft matter synthesis and characterization courses.

DEI and Service

Diverse and inclusive academic environments enhance student achievement, lead to the development of more innovative solutions, and increase the likelihood of scientific success (e.g., Hong and Page, PNAS, 2004). During my graduate work, I led, advocated for, and supported classroom-, department-, and Institute-level DEI initiatives which led to tangible impacts in curricula development and practices in recruiting, student orientation, and community-building. Now, as a postdoc, I am organizing the inaugural LGBTQIA+ Materials Research Symposium at the 2024 Materials Research Society Spring Meeting, providing a platform for LGBTQIA+ scientists to present their research to a diverse audience supportive of their identity and scientific capacity. Further, I am chairing the 2025 Polymers Gordon Research Symposium, where I look forward to uplifting the contributions of diverse polymer science researchers. I look forward to continuing this work towards enhancing diversity in admissions, creating inclusive institutional cultures, and promoting visibility and belonging for LGBTQIA+ scholars.