Thermoresponsive Pentablock Copolymer on Silica: Temperature Effects on Adsorption, Surface Forces, and FrictionShow others and affiliations
2019 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 35, no 3, p. 653-661Article in journal (Refereed) Published
Abstract [en]
The adsorption of hydrophilic or amphiphilic multiblock copolymers provides a powerful means to produce well-defined "smart" surfaces, especially if one or several blocks are sensitive to external stimuli. We focus here on an A-B-A-B-A copolymer, where A is a cationic poly((3-acrylamido-propyl)-trimethylammonium chloride) (PAMPTMA) block containing 15 (end blocks) or 30 (middle block) repeat units and B is a neutral thermosensitive water-soluble poly(2-isopropyl-2-oxazoline) (PIPOZ) block with 50 repeat units. X-ray reflectivity and quartz crystal microbalance with dissipation monitoring were employed to study the adsorption of PAMPTMA15-PIPOZ50-PAMPTMA30-PIPOZ50-PAMPTMA15 on silica surfaces. The latter technique was employed at different temperatures up to 50 °C. Surface forces and friction between the two silica surfaces across aqueous pentablock copolymer solutions at different temperatures were determined with the atomic force microscopy colloidal probe force and friction measurements. The cationic pentablock copolymer was found to have a high affinity to the negatively charged silica surface, leading to a thin (2 nm) and rigid adsorbed layer. A steric force was encountered at a separation of around 3 nm from hard wall contact. A capillary condensation of a polymer-rich phase was observed at the cloud point of the solution. The friction forces were evaluated using Amontons' rule modified with an adhesion term.
Place, publisher, year, edition, pages
2019. Vol. 35, no 3, p. 653-661
Keywords [en]
Adsorption, Atomic force microscopy, Chlorine compounds, Polyethylenes, Silica, Sols, Capillary condensation, External stimulus, Friction measurements, Multiblock co-polymers, Negatively charged, Pentablock copolymers, Quartz crystal microbalance with dissipation monitoring, X ray reflectivity, Friction
National Category
Natural Sciences
Identifiers
URN: urn:nbn:se:ri:diva-37700DOI: 10.1021/acs.langmuir.8b03729Scopus ID: 2-s2.0-85060374990OAI: oai:DiVA.org:ri-37700DiVA, id: diva2:1284782
Note
Funding details: National Science Foundation, NSF, NSF OISE 1358179; Funding details: Natural Sciences and Engineering Research Council of Canada, NSERC; Funding details: 2015-05080; Funding text 1: This work is supported by the Swedish Research Council, VR, contract number [2015-05080] and F.M.W. acknowledges grants from the Natural Science and Engineering Research Council of Canada and of MEXT Japan (World Premier Initiative). M.C.R. acknowledges funding through the National Science Foundation under award NSF OISE 1358179.
2019-02-012019-02-012023-03-30Bibliographically approved