FRINK Linked Data Fragments server

Matches in SemOpenAlex for { <https://semopenalex.org/work/W2892282296> ?p ?o ?g. }

• W2892282296 abstract "This work study a monolayer of branched poly(ethyleneimine (PEI) adsorbed onto oppositely charged surfaces with iron chelates or iron ions in the absorption solution. The conformation of adsorbed PEI is explored in the dependence of the composition of the adsorption solution by measuring the surface forces using atomic force microscopy (AFM) with the colloidal probe (CP) at different ionic strengths (INaCl) in surrounding aqueous solution. The surface coverage of these layers is investigated using X-ray reflectivity.PEI solutions show different pH values with iron chelates (pH = 3), iron ions (pH = 4.67) or pure water (pH = 9.3) at room temperature. Low surface coverage of PEI at pH = 3 adjusted by monovalent ions was also observed. However, adsorbing PEI with iron ions or iron chelates and washing with pure water shifts the pH, leading to an adsorbed PEI layer with high coverage. In our observation, the influence of iron ions and iron chelates on the surface coverage of PEI film is stronger than the pH effect. PEI adsorbed from a pure water solution shows flat conformation. Surface force measurements with CP show that PEI adsorbed from solutions containing iron chelates or iron ions cause almost identical steric forces. The thickness of the brush L is determined as a function of the ionic INaCl in the measuring solution. It scales as a polyelectrolyte brush. The maximum number density of gold nanoparticles (AuNPs) adsorbed onto the PEI brushes was identical and larger than on flatly adsorbed PEI. On the PEI layer with the larger surface coverage, the AuNPs aggregate; on the PEI layer with the lower surface coverage they do not aggregate. Taken together, these results contribute to understanding the mechanisms determining surface coverage and conformation of PEI and demonstrate the possibility of controlling surface properties, which is highly desirable for potential future applications. In this thesis, we also investigate the top layer (PSS and PDADMA) of polyelectrolyte multilayer (PEM) films. PEM films were prepared by sequential adsorption of oppositely charged PEs on solid substrates. PEM films consist of polydiallyldimethylammonium (PDADMA) as polycation and the polystyrene sulfonate (PSS) as polyanion. PDADMA has a smaller linear charge density than PSS. For this system, two different growth regimes are known: parabolic and linear. I studied the top layer (PSS and PDADMA) conformation of PEM films and how the structure of this top layer is affected by increasing the number of PDADMA/PSS layer pairs N and the addition of salt to the surrounding solution. The INaCl was changed during the force-distance measurements. PSS terminated films always show electrostatic forces at INaCl 0.1 M, a non-electrostatic action occurs and the PSS terminated film reswells in solution. PDADMA terminated surface consisting of few layers show a flat conformation and the electrostatic forces were measured. For N ≥ 9 and INaCl ≤ 0.1 M, steric forces were measured. The force-distance profiles are well-explained by Alexander and de Gennes theory. PDADMA chains show a maximum L that is around 40-45 % of the contour length. For INaCl ≈ 0.1 M, and N > 9, a flat, neutral or zwitterionic surface is found (λ-1 ≈ 0.3-0.9 nm). For N = 9 and INaCl > 0.1 M, a strong screening of electrostatic interaction and attractive forces are observed. For N > 9 and INaCl > 0.1 M, the ion adsorption into the PE chains leads to an increase in the monomer size and as a result, the L increases and PDADMA brushes reswell again into the solution.These data show that by varying N and INaCl, different surface forces can be obtained: Electrostatic forces (flat chains) both positive and negative, steric forces (brush), hydration force (flat, neutral or zwitterionic surface), and effects not yet explained (reswelling brush)." @default.
• W2892282296 created "2018-09-27" @default.
• W2892282296 creator A5086822429 @default.
• W2892282296 date "2018-08-30" @default.
• W2892282296 modified "2023-09-27" @default.
• W2892282296 title "Surface Forces Characterization of Polyelectrolyte Monolayers and Multilayers" @default.
• W2892282296 hasPublicationYear "2018" @default.
• W2892282296 type Work @default.
• W2892282296 sameAs 2892282296 @default.
• W2892282296 citedByCount "0" @default.
• W2892282296 crossrefType "journal-article" @default.
• W2892282296 hasAuthorship W2892282296A5086822429 @default.
• W2892282296 hasConcept C145148216 @default.
• W2892282296 hasConcept C147789679 @default.
• W2892282296 hasConcept C150394285 @default.
• W2892282296 hasConcept C153356533 @default.
• W2892282296 hasConcept C178790620 @default.
• W2892282296 hasConcept C179104552 @default.
• W2892282296 hasConcept C184651966 @default.
• W2892282296 hasConcept C185592680 @default.
• W2892282296 hasConcept C187428577 @default.
• W2892282296 hasConcept C197404232 @default.
• W2892282296 hasConcept C2182769 @default.
• W2892282296 hasConcept C521977710 @default.
• W2892282296 hasConcept C55493867 @default.
• W2892282296 hasConcept C59789625 @default.
• W2892282296 hasConcept C7070889 @default.
• W2892282296 hasConceptScore W2892282296C145148216 @default.
• W2892282296 hasConceptScore W2892282296C147789679 @default.
• W2892282296 hasConceptScore W2892282296C150394285 @default.
• W2892282296 hasConceptScore W2892282296C153356533 @default.
• W2892282296 hasConceptScore W2892282296C178790620 @default.
• W2892282296 hasConceptScore W2892282296C179104552 @default.
• W2892282296 hasConceptScore W2892282296C184651966 @default.
• W2892282296 hasConceptScore W2892282296C185592680 @default.
• W2892282296 hasConceptScore W2892282296C187428577 @default.
• W2892282296 hasConceptScore W2892282296C197404232 @default.
• W2892282296 hasConceptScore W2892282296C2182769 @default.
• W2892282296 hasConceptScore W2892282296C521977710 @default.
• W2892282296 hasConceptScore W2892282296C55493867 @default.
• W2892282296 hasConceptScore W2892282296C59789625 @default.
• W2892282296 hasConceptScore W2892282296C7070889 @default.
• W2892282296 hasLocation W28922822961 @default.
• W2892282296 hasOpenAccess W2892282296 @default.
• W2892282296 hasPrimaryLocation W28922822961 @default.
• W2892282296 hasRelatedWork W1970602086 @default.
• W2892282296 hasRelatedWork W1971892692 @default.
• W2892282296 hasRelatedWork W1973390431 @default.
• W2892282296 hasRelatedWork W1980783785 @default.
• W2892282296 hasRelatedWork W1981194038 @default.
• W2892282296 hasRelatedWork W1996242269 @default.
• W2892282296 hasRelatedWork W2001215679 @default.
• W2892282296 hasRelatedWork W2008729524 @default.
• W2892282296 hasRelatedWork W2016118577 @default.
• W2892282296 hasRelatedWork W2028116311 @default.
• W2892282296 hasRelatedWork W2031619054 @default.
• W2892282296 hasRelatedWork W2071760672 @default.
• W2892282296 hasRelatedWork W2078956170 @default.
• W2892282296 hasRelatedWork W2083858876 @default.
• W2892282296 hasRelatedWork W2085100200 @default.
• W2892282296 hasRelatedWork W2091559528 @default.
• W2892282296 hasRelatedWork W2094448574 @default.
• W2892282296 hasRelatedWork W2324667280 @default.
• W2892282296 hasRelatedWork W2334056172 @default.
• W2892282296 hasRelatedWork W2797279353 @default.
• W2892282296 isParatext "false" @default.
• W2892282296 isRetracted "false" @default.
• W2892282296 magId "2892282296" @default.
• W2892282296 workType "article" @default.