Preparation and Characterization of Mono- and Multilayer Films of Polymerizable 1,2-Polybutadiene Using the Langmuir–Blodgett Technique

Abstract

The essence of this study is to apply the Langmuir-Blodgett (LB) technique for assembling asymmetric membranes. Accordingly, Langmuir films of a (further) polymerizable polymer, 1,2-polybutadiene (1,2-pbd), were studied and transferred onto different solid supports, such as gold, indium tin oxide (ITO), and silicon. The layers were characterized both at the air/water interface as well as on different substrates using numerous methods including cyclic voltammetry, impedance spectroscopy, spectroscopic ellipsometry, atomic force microscopy, X-ray photoelectron spectroscopy, and reflection-absorption Fourier transform infrared spectroscopy. The Langmuir films were stable at the air-water interface as long as they were not exposed to UV irradiation. The LB films formed disorganized layers, which gradually blocked the permeation of different species with increasing the number of deposited layers. The thickness was ca. 4-7 Å per layer. Irradiating the Langmuir films caused their cross-linking at the air-water interface. Furthermore, we took advantage of the reactivity of the double bond of the LB films on the solid supports and graft polymerized acrylic acid on top of the 1,2-pbd layers. This approach is the basis of the formation of an asymmetric membrane that requires different porosity on both of its sides.

Confinement and Cross-Linking of 1,2-Polybutadiene in Two Dimensions at the Air–Water Interface

“…Otherwise, aggregates are formed due to the hydrophobic nature of the polymer. Even though, to our knowledge, the oxidation of PB in Langmuir monolayers has never been addressed, ,, its sensitivity to natural light is not surprising considering the nanometer thickness of the studied layer. Indeed, it has been evidenced that photo-oxidation is a surface phenomenon. , Coquillat et al have highlighted a critical sample thickness (L c = 22 +/– 2 μm) beyond which oxidation is no longer homogeneous leading to an oxidation gradient due to oxygen diffusion …”

“…Matmour et al showed the feasibility of cross-linking a triethoxysilane-functionalized PB Langmuir monolayer, through an acid-catalyzed condensation reaction . To our knowledge, only two studies report in situ characterization of a pure PB polymer or oligomer monolayers. , In particular, Hitrik et al investigated the effect of UV-irradiating pure PB monolayers. They showed a significant contraction of the monolayer upon a long UV irradiation reflecting its cross-linking.…”

“…17 To our knowledge, only two studies report in situ characterization of a pure PB polymer or oligomer monolayers. 24,25 In particular, Hitrik et al 24 investigated the effect of UVirradiating pure PB monolayers. They showed a significant contraction of the monolayer upon a long UV irradiation reflecting its cross-linking.…”

In-chain functionalized syndiotactic 1,2-polybutadiene by a Ziegler–Natta iron(iii) catalytic system

“…[3][4][5][6][7] Due to its unique mechanical properties that originate from the combination of properties of plastic and rubber, sPB reveals a wide range of applications in the elds of bres, lms, moulded articles, and recently has been used as synthetic rubber reinforcing llers. [8][9][10][11][12] Despite this, the inherent shortfall of low surface energy makes sPB display inferior properties with respect to adhesion, toughness, paintability, miscibility and rheological properties. Improving the hydrophilicity and developing functionalized sPB has been the long-term pursuit for scientists.…”

In Situ Electrodeposition of an Asymmetric Sol–Gel Membrane Based on an Octadecyltrimethoxysilane Langmuir Film

“…We have also demonstrated the application of the LB method for the formation of an asymmetric membrane. [8] Specifically, a Langmuir film of polymerizable 1,2-polybutadiene was transferred onto a solid support on which the backbone polymer was grown by graft polymerization.…”