Interpenetration of chemically identical polymer onto grafted substrates. (15th September 2015)

• Record Type: Journal Article
• Authors: Lee, Hoyeon; Jo, Seongjun; Hirata, Toyoaki; Yamada, Norifumi L.; Tanaka, Keiji; Kim, Eunkyoung; Ryu, Du Yeol
• Is Part Of: Polymer. Volume 74(2015)
• Page Start: 70
• Page End: 75
• Publication Date: 2015-09-15
• Subjects: Interpenetration -- Grafted substrate -- Thin film; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; 547.7
• DOI: 10.1016/j.polymer.2015.07.054
• Languages: English
• ISSNs: 0032-3861

Abstract

Abstract: Interpenetrating interfaces between a deuterated polystyrene (dPS) and the grafted substrates with the same chemical identity were characterized using neutron reflectivity (NR) measurements, where the PS-grafted substrates were prepared using a grafting-to approach with hydroxyl end-functionalized polystyrene (PSOH) in a dry brush regime. The characteristic brush thickness ( h ) and grafting density ( σ ) of PS-grafted layers were determined based on the chain length (or molecular weight, M n ) of PSOHs. The experimental interpenetration length ( ξ ) was measured at the interfaces, and the limiting plateau in ξ above which the value was independent of film thickness shifted toward higher values as the M n of PSOH increased. Normalization by the deformed brush thickness ( h d ) of PS-grafted layer after interpenetration revealed that the experimental value of ξ / h d in a short and dense PS-grafted substrate, prepared with a low-molecular-weight PSOH, deviated markedly from the theoretical value, indicating significant additional stretching of the grafted chains to accommodate inter-mixing with the dPS chains. Graphical abstract: Highlights: Interpenetration behavior of chemically identical polymers onto the grafted substrates. Model layer system to examine interpenetrating interfaces in a dry brush regime. Evaluation of the interpenetration length ( ξ ) at the interfaces between a dPS and PS-grafted layers. Effective diffusion of the dPS chains onto a short and dense PS-grafted layer.