*Seminar Series: Chemistry seminar
*Location: AIBN Seminar Room
*Date: 22/05/2017
*Time: 13:00

Speaker #1 details
*Title of talk: Advancing our understanding of responsive polymer brush coatings
*Speaker's name: Prof. Erica Wanless
*Speaker's organisation: University of Newcastle
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Talk Abstract: Controlling the interactions between surfaces and their environment is pertinent to the performance of a wide range of formulations and technologies. These interactions can be modified by the presence of a polymer surface coating. Terminally anchored polymer brushes offer an attractive route to regulate surface behaviour through reversible manipulation of colloidal-scale interactions. Through changes in conformation in response to the aqueous phase temperature, pH or electrolyte concentration, a polymer brush coating offers a means, for example, of dictating the wettability, adhesion or friction of a surface. The response of the polymer brushes to changes in the adjacent aqueous solution have been investigated using in situ ellipsometry, quartz crystal microbalance with dissipation, atomic force microscopy, contact angle and neutron reflectometry measurements. This powerful suite of characterisation methods has enabled us to interpret the coating conformational response in terms of brush thickness, changes in the brush depth profile from neutron reflectometry, and the surface response from contact angle changes.

The focus of our studies has been the family of weakly basic poly(2-dimethylamino)ethyl methacrylate) brushes together with the increasingly hydrophobic poly(2-diethylamino) and poly(2-diisopropylamino) analogues.[1-5] We have characterised the pH-response of this family of polymer brushes through both kinetic and equilibrium measurements. The delicate balance between the charging behaviour of these brushes and their hydrophobicity led us to investigate the impact of ionic strength on their response.[1] Significantly, the brush behaviour was determined to be not only ionic strength-dependent but is also influenced by the nature of the added salt based on its position in the well-known Hofmeister series.[3-5] Recently we have found similarly strong anion specific effects in the thermoresponse of poly(N-isopropylacrylamide)[6-7] and ethylene glycol-based[8] brushes. The influence of ion identity on polymer brush response is an area of ongoing investigation and will be the focus of this presentation.

References
1 J.D. Willott et al., Langmuir 2014, 30(7), 1827. DOI: 10.1021/la4047275
2 J.D. Willott et al., Phys. Chem. Chem. Phys., 2015, 17, 3880. DOI: 10.1039/C4CP05292G
3 J.D. Willott et al., Langmuir, 2015, 31(12), 3707. DOI: 10.1021/acs.langmuir.5b00116
4 J.D. Willott et al., Macromolecules, 2016, 49, 2327. DOI: 10.1021/acs.macromol.5b02656
5 T.J. Murdoch et al., Macromolecules, 2016, 49, 9605. DOI: 10.1021/acs.macromol.6b01897
6 B.A. Humphreys et al., Phys. Chem. Chem. Phys. 2016, 18, 6037. DOI: 10.1039/C5CP07468A
7 T.J. Murdoch et al., Macromolecules,2016, 49, 6050. DOI:10.1021/acs.macromol.6b01001
8 T.J. Murdoch et al., J. Colloid Interface Sci. ,2017, 490, 869. DOI: 10.1016/j.jcis.2016.11.04
Speaker's bio: Prof. Wanless' website is: https://www.newcastle.edu.au/profile/erica-wanless

Speaker #2 details
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Other Details: Anybody wishing to meet with Prof. Wanless may contact Elizabeth Krenske.
*Host name: Elizabeth Krenske
Host phone number:
*Host email: e.krenske@uq.edu.au