Topological biopassive brushes. From linear to cyclic, from atomistic to coarse-grained poly(2-ethyl-2-oxazoline)
Embargoed until 2024-07-22
Date
2023Type
- Working Paper
ETH Bibliography
yes
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Abstract
Novel materials are always needed in medicine to ensure that what enters the human body is more biopassive, less toxic and has properties that better serve its cause compared to its predecessors. Linear or also ring poly(2-ethyl-2-oxazoline) (PEOXA) seems to be a valuable candidate for this purpose, surpassing its predecessor polyethylenglycol (PEG) in applications for which PEG is routinely used. The present work aims at elucidating the origins of the mechanical properties of PEOXA using a multiscale approach. To this end, atomistic simulations are employed to study a single PEOXA chain (of both linear and ring architecture) in water. The various atomistic force fields (FF) used indicate the existence of a secondary, helix-like structure as a result of hydrogen bond bridges along the polymer chain. Using the results of the atomistic simulations, we proceed to the creation of a coarse-grained (CG) model for the single PEOXA chain in water in order to be able to study the nanotribological properties of PEOXA in a computationally efficient way. This model is then used for the construction of PEOXA polymer brushes of various grafting densities, 휎, which we compress and shear so as to retrieve their nanotribological properties, such as the coefficient of friction. Brushes of ring architecture show lower coefficient of friction, which additionally seems to be rather indifferent to the increase of the grafting density within some limits, when sheared against an explicit CG wall. The equivalent values for the linear brushes seem to increase for lower grafting densities. Although when shearing against a symmetric linear brush, the opposite phenomenon is observed. Show more
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https://doi.org/10.3929/ethz-b-000623370Publication status
publishedPublisher
ETH ZurichSubject
polymer brushes; compression; Shear; friction; hydrogen bonds; secondary structure; PEOXA; 2-ethyl-2-oxazoline; linear chain; ring chainOrganisational unit
ETH Zürich
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ETH Bibliography
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