Friday, 22 September 11:00am – 12:00pm

This seminar will be delivered in Chemistry Lecture Theatre 2

Speaker: Dr Isaac Gresham, University of Sydney

Host: Dr David Nguyen

Title: Nanostructure explains the behaviour of slippery covalently-attached liquid surfaces

Abstract: Slippery covalently attached liquid surfaces (SCALS) have recently attracted attention due to their exceptional properties, including low contact angle hysteresis (CAH), anti-fouling, and lubricative characteristics [1]. While these properties are generally attributed to the liquid-like mobility of the thin layer of tethered liquid polymers that comprise SCALS, there is still a need to better understand the underlying dynamics and physicochemical parameters that produce these desirable characteristics. [2].

In this seminar, we will present the comprehensive characterisation of the physicochemical structure of polydimethylsiloxane SCALS prepared using established methods [3-6]. We use single-molecule force spectroscopy and neutron reflectometry (interpreted using numerical self-consistent field theory) to quantify the chain length, polydispersity, thickness, and grafting density of the SCALS. We will then correlate these parameters with the CAH of the respective layer.

Our results explain the SCALS performance discrepancies reported in the literature [3-6] and provide insight into the specific physicochemical parameters required to optimise SCALS function, thereby enabling their rational design.

1. Gresham, I. J. & Neto C. Adv Colloid Interface Sci.2023, 10.1016/j.cis.2023.102906
2. Zhao, X. et. al. ACS Nano2021, 10.1021/acsnano.1c04386.
3. Wang, L. & Mccarthy, T. J. Angewandte Chemie International Edition2016, 10.1002/anie.201509385
4. Krumpfer, J. W. & Mccarthy, T. J. Langmuir2011, 10.1021/la202583w
5. Zhang, L. et al. ACS Appl Mater Interfaces2020, 10.1021/acsami.0c02014.
6. Teisala, H. et. al. Langmuir2020, 10.1021/acs.langmuir.9b03223

Bio: Isaac is a postdoctoral researcher at the University of Sydney in the group of Prof. Chiara Neto, working to understand the fundamental reasons for the slipperyness of tethered oil molecules. He completed his PhD at the University of New South Wales under A/Prof. Stuart Prescott, where he used neutron reflectometry (as well as other, less exciting techniques) to study the structure of tethered responsive polymer systems using neutron reflectometry. His research interests include the measurement of tethered molecule dynamics, polymer-surfactant interaction, freeform modelling techniques, and the application of Bayesian statistics to scattering/reflectometry analysis.