Characterization of layer-by-layer self-assembled multilayer films of diblock copolymer micelles

Sakai, Kenichi, Webber, Grant B., Vo, Cong-Duan, Wanless, Erica J., Vamvakaki, Maria, Butun, Vural, Armes, Steven P. and Biggs, Simon (2008) Characterization of layer-by-layer self-assembled multilayer films of diblock copolymer micelles. Langmuir, 24 1: 116-123. doi:10.1021/la7021006

Author Sakai, Kenichi
Webber, Grant B.
Vo, Cong-Duan
Wanless, Erica J.
Vamvakaki, Maria
Butun, Vural
Armes, Steven P.
Biggs, Simon
Title Characterization of layer-by-layer self-assembled multilayer films of diblock copolymer micelles
Journal name Langmuir   Check publisher's open access policy
ISSN 0743-7463
Publication date 2008-01-01
Sub-type Article (original research)
DOI 10.1021/la7021006
Open Access Status
Volume 24
Issue 1
Start page 116
End page 123
Total pages 8
Place of publication Washington, DC, United States
Publisher American Chemical Society
Language eng
Abstract The in situ layer-by-layer (LbL) self-assembly of low T g diblock copolymer micelles onto a flat silica substrate is reported. The copolymers used here were a cationic poly(2-(dimethylamino)ethyl methacrylate)-block- poly(2-(diethylamino)ethyl methacrylate) (50qPDMA-PDEA; 50q refers to a mean degree of quaternization of 50 mol % for the PDMA block) and zwitterionic poly(methacrylic acid)-block-poly(2-(diethylamino)ethyl methacrylate) (PMAA-PDEA), which has anionic character at pH 9. Alternate deposition of micelles formed by these two copolymers onto a silica substrate at pH 9 was examined. The in situ LbL buildup of the copolymer micelle films was monitored using ζ potential measurements, optical reflectometry, and a quartz crystal microbalance with dissipation monitoring (QCM-D). For a six layer deposition, complete charge reversal was observed after the addition of each layer. The OR data indicated clearly an increase in adsorbed mass with each additional micelle layer and suggest that some interdiffusion of copolymer chains between layers and/or an increase in the film roughness, and hence in the effective surface area of the micellar multilayers, must take place as the film is built up. QCM-D data indicated that the self-assembled micellar multilayers on a flat silica substrate undergo structural changes over a prolonged period. This is attributed to longer-term interdiffusion of the copolymer chains between the outer two layers after the initial adsorption of each layer is complete. The QCM-D data further suggest that the outer adsorbed layers adopt a progressively more extended conformation, particularly for the higher numbered layers. The morphology of each successive layer was characterized using in situ soft-contact atomic force microscopy, and micelle-like surface aggregates are clearly observed within each layer of the complex film, suggesting the persistence of aggregate structures throughout the multilayer structure.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: Faculty of Engineering, Architecture and Information Technology Publications
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