SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "WFRF:(Teixeira C. V.) srt2:(2003-2004)"

Sökning: WFRF:(Teixeira C. V.) > (2003-2004)

  • Resultat 1-3 av 3
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
1.
  • Flodström, Katarina, et al. (författare)
  • In situ synchrotron small-angle X-ray scattering/X-ray diffraction study of the formation of SBA-15 mesoporous silica
  • 2004
  • Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 20:12, s. 4885-4891
  • Tidskriftsartikel (refereegranskat)abstract
    • The initial stages of the formation of SBA-15 have been studied by in situ SAXS/XRD using synchrotron radiation. Modeling of both the diffuse scattering and the X-ray diffraction patterns obtained at different stages of the reaction results in a detailed description of the different reaction steps. The first step in the formation is the liquid-liquid phase separation of spherical P123-silicate hybrid micelles after which nucleation and growth of the 2D hexagonal phase occurs. Two-dimensional electron density maps calculated on the basis of the intensities of the Bragg reflections suggest that changes in the degree of intermicellar condensation are responsible for the time-dependent observations. The silica source (alkoxysilanes) may be partially unhydrolyzed long after formation of the hexagonal structure, since the kinetics of the mesophase evolution is notably slower when TEOS is used as the silica precursor as compared to TMOS. The results obtained for SBA-15 are compared with other published data on the formation of SBA-15 and of the smaller pore MCM-41 materials.
  •  
2.
  • Flodström, Katarina, et al. (författare)
  • Time-resolved in situ studies of the formation of cubic mesoporous silica formed with triblock copolymers
  • 2004
  • Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 20:23, s. 10311-10316
  • Tidskriftsartikel (refereegranskat)abstract
    • The mechanism of formation of two different cubic mesoporous silica materials formed with Pluronic triblock copolymers is investigated with in situ time-resolved small-angle synchrotron X-ray scattering, in situ time-resolved H-1 nuclear magnetic resonance, and time-resolved transmission electron microscopy. The materials studied are the micellar cubic (Im (3) over barm) SBA-16 formed with Pluronic F108 and the bicontinuous cubic (Ia (3) over bard) silica material formed with Pluronic P103 and NaI. The formation mechanisms of the two cubic structures are shown to be dissimilar. For the Im (3) over barm material, in the early stages of the synthesis, floes of unordered micelles are observed, but areas where the micelles have started to order are also present. With time, there is an increase in order; however, there is a coexistence of unordered micelles and ordered material all through this study. The bicontinuous cubic silica is formed via a different path. The system is phase-separated already before the addition of the silica source, which implies that a concentrated phase is present, acting as the structure director of the Ia (3) over bard structure. The results are compared with earlier reports on the formation of the hexagonal SBA-15 material.
  •  
3.
  • Prates, M L, et al. (författare)
  • On the qualification of multiplayer thin film coatings
  • 2003
  • Ingår i: Proceedings 1st International Meeting of Sciences and Technology of Design "Senses and Sensibility in Technology - Linking Tradition to Innovation through Design" September. - Lisbon, Portugal.
  • Konferensbidrag (refereegranskat)
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 1-3 av 3

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy