Ändra sökning
RefereraExporteraLänk till posten
Permanent länk

Direktlänk
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Tethered Poly(2-isopropyl-2-oxazoline) Chains: Temperature Effects on Layer Structure and Interactions Probed by AFM Experiments and Modeling
KTH, Skolan för kemivetenskap (CHE), Kemi.
KTH, Skolan för kemivetenskap (CHE), Kemi.
KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi. SP Technical Research Institute of Sweden, Sweden .ORCID-id: 0000-0002-2288-819X
Visa övriga samt affilieringar
2015 (Engelska)Ingår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 31, nr 10, s. 3039-3048Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Thermoresponsive polymer layers on silica surfaces have been obtained by utilizing electrostatically driven adsorption of a cationic-nonionic diblock copolymer. The cationic block provides strong anchoring to the surface for the nonionic block of poly(2-isopropyl-2-oxazoline), referred to as PIPOZ. The PIPOZ chain interacts favorably with water at low temperatures, but above 46 degrees C aqueous solutions of PIPOZ phase separate as water becomes a poor solvent for the polymer. We explore how a change in solvent condition affects interactions between such adsorbed layers and report temperature effects on both normal forces and friction forces. To gain further insight, we utilize self-consistent lattice mean-field theory to follow how changes in temperature affect the polymer segment density distributions and to calculate surface force curves. We find that with worsening of the solvent condition an attraction develops between the adsorbed PIPOZ layers, and this observation is in good agreement with predictions of the mean-field theory. The modeling also demonstrates that the segment density profile and the degree of chain interpenetration under a given load between two PIPOZ-coated surfaces rise significantly with increasing temperature.

Ort, förlag, år, upplaga, sidor
2015. Vol. 31, nr 10, s. 3039-3048
Nationell ämneskategori
Kemi Fysik
Identifikatorer
URN: urn:nbn:se:kth:diva-165219DOI: 10.1021/la504653wISI: 000351327300013PubMedID: 25686020Scopus ID: 2-s2.0-84925004133OAI: oai:DiVA.org:kth-165219DiVA, id: diva2:810152
Anmärkning

QC 20150506

Tillgänglig från: 2015-05-06 Skapad: 2015-04-24 Senast uppdaterad: 2017-12-04Bibliografiskt granskad
Ingår i avhandling
1. Polymers in Aqueous Lubrication
Öppna denna publikation i ny flik eller fönster >>Polymers in Aqueous Lubrication
2017 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

The main objective of this thesis work was to gain understanding of the layer properties and polymer structures that were able to aid lubrication in aqueous media. To this end, three types of polyelectrolytes: a diblock copolymer, a train-of-brushes and two brush-with-anchor mucins have been utilized. Their lubrication ability in the boundary lubrication regime has been examined by Atomic Force Microscopy with colloidal probe.

The interfacial behavior of the thermoresponsive diblock copolymer, PIPOZ60-b-PAMPTAM17,on silica was studied in the temperature interval 25-50 ˚C. The main finding is that adsorption hysteresis, due to the presence of trapped states, is important when the adsorbed layers are in contact with a dilute polymer solution. The importance of trapped states was also demonstrated in the measured friction forces, where significantly lower friction forces, at a given temperature, were encountered on cooling than on the preceding heating stage, which was attributed to increased adsorbed amount. On the heating stage the friction force decreased with increasing temperature despite the worsening of the solvent condition, and the opposite trend was observed when using pre-adsorbed layers (constant adsorbed amount) as a consequence of increased segment-segment attraction.

The second part of the studies was devoted to the interfacial properties of mucins on PMMA. The strong affinity provided by the anchoring group of C-PSLex and C-P55 together with their more extended layer structure contribute to the superior lubrication of PMMA compared to BSM up to pressures of 8-9 MPa. This is a result of minor bridging and lateral motion of molecules along the surface during shearing. We further studied the influence of glycosylation on interfacial properties of mucin by utilizing the highly purified mucins, C-P55 and C-PSLex. Our data suggest that the longer and more branched carbohydrate side chains on C-PSLex provide lower interpenetration and better hydration lubrication at low loads compared to the shorter carbohydrate chains on C-P55. However, the longer carbohydrates appear to counteract disentanglement less efficiently, giving rise to a higher friction force at high loads.

Ort, förlag, år, upplaga, sidor
Stockholm: KTH Royal Institute of Technology, 2017. s. 66
Serie
TRITA-CHE-Report, ISSN 1654-1081 ; 2017:15
Nyckelord
Lubrication, boundary lubrication, friction, surface forces, adsorption, adsorption hysteresis, non-equilibrium state, diblock copolymer, polyelectrolyte, thermoresponsive, mucin, QCM-D, ellipsometry, AFM
Nationell ämneskategori
Fysikalisk kemi
Forskningsämne
Kemi
Identifikatorer
urn:nbn:se:kth:diva-204931 (URN)978-91-7729-305-7 (ISBN)
Disputation
2017-03-31, Kollegiesalen, Brinellvägen 8, KTH-campus, Stockholm, 10:00 (Engelska)
Opponent
Handledare
Anmärkning

QC 20170407

Tillgänglig från: 2017-04-07 Skapad: 2017-04-04 Senast uppdaterad: 2017-04-07Bibliografiskt granskad

Open Access i DiVA

Fulltext saknas i DiVA

Övriga länkar

Förlagets fulltextPubMedScopus

Personposter BETA

Dedinaite, Andra

Sök vidare i DiVA

Av författaren/redaktören
An, JunxueLiu, XiaoyanDedinaite, AndraClaesson, Per M.
Av organisationen
KemiTillämpad fysikalisk kemiYt- och korrosionsvetenskap
I samma tidskrift
Langmuir
KemiFysik

Sök vidare utanför DiVA

GoogleGoogle Scholar

doi
pubmed
urn-nbn

Altmetricpoäng

doi
pubmed
urn-nbn
Totalt: 434 träffar
RefereraExporteraLänk till posten
Permanent länk

Direktlänk
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf