Jump to main content
Jump to site search

Issue 24, 2012
Previous Article Next Article

Structural aspects of polyanion and hydrophobically modified polycation multilayers on hydrophilic or hydrophobic surfaces

Author affiliations

Abstract

Multilayer films of carboxymethylcellulose (CMC), a polyanion, and bromide salts of poly(4-vinylpyridine) quaternized with linear aliphatic chains of 2 (ethyl) and 5 (pentyl) carbon atoms, coded as QPVP-C2 and QPVP-C5, respectively, were fabricated by layer-by-layer (LbL) self-assembly onto Si/SiO2 wafers (hydrophilic substrate) or polystyrene, PS, films (hydrophobic substrate). The films were characterized by means of ex situ and in situ ellipsometry, atomic force microscopy (AFM), contact angle measurements and sum frequency generation vibrational spectroscopy (SFG). Antimicrobial tests were used to assess the exposure of pyridinium moieties to the aqueous medium. In situ ellipsometry indicated that for Si/SiO2 the chains were more expanded than the PS films and both substrates systems composed of QPVP-C5 were thicker than those with QPVP-C2. For dried layers, the alkyl side group size had a small effect on the thickness evolution, regardless of the substrate. At pH 2 the multilayers showed high resistance, evidencing that the build-up is driven not only by cooperative polymerpolymer ion pairing, but also by hydrophobic interactions between the alkyl side chains. The LbL films became irregular as the number of depositions increased. After the last deposition, the wettability of QPVP-C2 or QPVP-C5 terminated systems on the Si/SiO2 wafers and PS films were similar, except for QPVP-C2 on Si/SiO2 wafers. Unlike the morphology observed for LbL films on Si/SiO2 wafers, PS induced the formation of porous structures. SFG showed that in air the molecular orientation of pyridinium groups in multilayers with QPVP-C5 was stronger than in those containing QPVP-C2. The exposure of pyridinium moieties to the aqueous medium was more pronounced when the LbL were assembled on Si/SiO2 wafers.

Graphical abstract: Structural aspects of polyanion and hydrophobically modified polycation multilayers on hydrophilic or hydrophobic surfaces

Back to tab navigation

Supplementary files

Publication details

The article was received on 21 Mar 2012, accepted on 13 Apr 2012 and first published on 15 May 2012


Article type: Paper
DOI: 10.1039/C2SM25658D
Citation: Soft Matter, 2012,8, 6462-6470
  •   Request permissions

    Structural aspects of polyanion and hydrophobically modified polycation multilayers on hydrophilic or hydrophobic surfaces

    J. Amim, F. C. B. Maia, P. B. Miranda, M. D. Urzúa and D. F. S. Petri, Soft Matter, 2012, 8, 6462
    DOI: 10.1039/C2SM25658D

Search articles by author

Spotlight

Advertisements