Wednesday, 2 April 2025 11:00am – 12:00pm

This seminar will be delivered in Chemistry Lecture Theatre 4

Speaker: Professor Justin Chalker

Host: Prof. Chiara Neto

Title: Organosulfur chemistry for night vision, gold mining, and recyclable plastics

Abstract
Approximately 80 million tonnes of sulfur are produced each year in petroleum refining. While much of this sulfur is used to make sulfuric acid, fertilisers and vulcanised rubber, there are still many millions of tonnes of excess sulfur that are stockpiled each year. Our lab is exploring new chemistry to convert this underused feedstock into valuable materials. Furthermore, we are interested in applying these materials to challenges in sustainability. In this presentation, I will share some recent discoveries in novel trisulfide chemistry and how our team has used this understanding to make poly(trisulfide) polymers that are generally recyclable. I will discuss three separate applications of these polymers: 1) Sustainable alternatives to the critical element germanium in optics for infrared thermal imaging;¹ 2) Recyclable gold sorbents for safer gold mining and e-waste recycling;^2,3 and 3) poly(trisulfide) analogues of plastics such as polyethylene that can be made, used, and “un-made” (depolymerised) when recycling is required.⁴

References:

1. Tonkin, S. J. et al. Thermal Imaging and Clandestine Surveillance using Low-Cost Polymers with Long-Wave Infrared Transparency. Advanced Optical Materials 2023, 11, 2300058.
2. Pople, J. M. M. et al. Electrochemical synthesis of poly(trisulfides). J. Am. Chem. Soc. 2023, 145, 11798-11810.
3. Mann, M. et al. Integrated methods for gold leaching and recovery from ore and electronic waste. Submitted. A preprint is available on ChemRxiv: 2024, DOI: 10.26434/chemrxiv-2024-1xd84.
4. Patel, H. D. et al. Spontaneous Trisulfide Metathesis in Polar Aprotic Solvents. Submitted. A preprint is available on ChemRxiv: 2025, DOI: 10.26434/chemrxiv-2025-fnhdd.

Bio
Justin M. Chalker is currently an ARC Future Fellow and Matthew Flinders Professor of Chemistry at Flinders University. Justin earned a B.S. in Chemistry and a B.A. in the History and Philosophy of Science at The University of Pittsburgh in 2006. At Pittsburgh, he contributed to the total synthesis of several natural products under the direction of Theodore Cohen. Supported by a Rhodes Scholarship and a National Science Foundation Graduate Research Fellowship, Justin then completed his D.Phil. at the University of Oxford under the supervision of Benjamin Davis where he developed several tools for the site-selective modification of proteins. In 2012, Justin started his independent career as an assistant professor at The University of Tulsa where he established a diverse research program in organic chemistry, biochemistry and material science. In 2015, Justin moved to Flinders University as a Lecturer in Synthetic Chemistry and recipient of an ARC Discovery Early Career Researcher Award, rising to rank of Professor in 2021. Justin has earned >$10M AUD in competitive funding for his scholarly activities and he has been recognised with several awards for his efforts in teaching and research. These include the SA Science Excellence Awards STEM Educator of the Year (2018) and the Prime Minister’s Prize for New Innovators (2020). Justin’s current research interests focus on fundamental sulfur chemistry and applied polymer technologies to address grand challenges in sustainability.