32.【Macromol. Rapid Commun.】Dense Monolayer Network Structures of Double Hydrophilic Hyperbranched Copolymers at the Air/Water Interface
作者：Yongliang Tu, Gangyao Wen*, Dimitrios Selianitis, and Stergios Pispas
關鍵字：Langmuir monolayers, Langmuir-Blodgett films, hyperbranched copolymers, network structures, honeycomb-like structures, subphase conditions
論文來源：期刊
具體來源：Macromol. Rapid Commun. 2024, 45(4), 2300548.
發表時間：2023年
Influences of subphase pH and temperature on the interfacial aggregation behavior of two double hydrophilic hyperbranched copolymers of poly[oligo(ethylene glycol) methacrylate-co-(2-diisopropylamino)ethyl methacrylate] (P(OEGMA-co-DIPAEMA)) at the air/water interface were studied by the Langmuir film balance technique. Morphologies of their Langmuir-Blodgett (LB) films were characterized by atomic force microscopy (AFM). At the interface, P(OEGMA-co-DIPAEMA) copolymers tend to form a dense network structure of circular micelles composed of branching agent-connected carbon backbone cores and mixed shells of OEGMA and DIPAEMA segments (pendant groups). This network structure containing many honeycomb-like holes with diameters of 6-8 nm is identified for the first time and clearly observed in the enlarged AFM images of their LB films. Under acidic conditions, surface pressure versus molecular area isotherms of the two copolymers in the low pressure region show larger mean molecular area than those under neutral and alkaline conditions due to the lack of impediment from DIPAEMA segments. Upon further compression, each isotherm exhibits a wide pseudo-plateau, which corresponds to OEGMA segments being pressed into the subphase. Furthermore, the isotherms under neutral and alkaline conditions exhibit the lower critical solution temperature behavior of OEGMA segments, and the critical temperature is lower when the hyperbranched copolymer contains higher OEGMA content.
Article link: https://doi.org/10.1002/marc.202300548
Read-only version: https://onlinelibrary.wiley.com/share/author/DY9ZNUUWQYUEQPWEC9G2?target=10.1002/marc.202300548