Photochemical Stabilization of Ultrathin Polymer Films Prepared by the Langmuir-Blodgett Technique

Hayashi, Takanori; Mabuchi, Mahito; Mitsuishi, Masaya; Ito, Shinzaburo; Yamamoto, Masahide; Knoll, Wolfgang

doi:10.1021/ma00111a057

Cited by 10 publications

(7 citation statements)

References 6 publications

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“…In addition, in some cases, it has been shown that the stability of a polymer Langmuir monolayer can be strengthened through cross-linking reactions performed either in situ or after monolayer transfer onto a substrate. Well-ordered two-dimensional (2D) polymer networks have also been synthesized starting from monomers. − In some cases, improved mechanical or thermal properties are evidenced. ,,− Among the different reaction pathways available, free-radical cross-linking using UV irradiation is the main mechanism used at the air–water interface. Indeed, UV light has the advantage of simplicity of use, avoiding the introduction of a cross-linking agent in the subphase and allowing a spatial control of the reaction at a local scale .…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2020

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Langmuir monolayers of 1,2-polybutadiene (PB) were investigated by means of surface pressure−area isotherms, Brewster angle microscopy (BAM) observations, and sumfrequency generation (SFG) spectroscopy. A homogeneous and stable monolayer is formed 1.5 h after PB spreading provided that both light and oxygen are present. This was attributed to a slight oxidation of the PB at the air−water interface. The cross-linking of PB under UV photoirradiation was then studied. SFG spectroscopy demonstrates the in situ formation of a two-dimensional network. From surface pressure−area characterizations and BAM experiments, the cross-linked PB monolayer appears significantly denser and more rigid than the non-irradiated monolayer. Atomic force microscopy images reveal an increase by a factor of three in the root-mean-square roughness of the irradiated monolayers compared with the non-irradiated ones.

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Section: Introductionmentioning

confidence: 99%

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

et al. 2020

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“…Furthermore, we have also succeeded in the introduction of various functional groups such as redox species, aromatic chromophores, and chiral groups into the polymer LB films as a comonomer of DDA. A few examples of cross-linkable polymer LB films, for example, poly(styrene- co -maleic anhydride) derivatives for electron beam resists, poly(vinylpyridine) derivatives for patterning, and poly(vinyl acetal) and polyglutamate derivatives for thermal stability, have been reported. No reports on molecular patterning using cross-linkable polymer LB films are available in the literature to date.…”

Section: Introductionmentioning

confidence: 99%

Photopatterning Using a Cross-Linkable Polymer Langmuir−Blodgett Film

Aoki¹,

Nakaya²,

Miyashita³

1998

Macromolecules

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A cross-linkable amphiphilic copolymer of N-dodecylacrylamide with N-(11-acryloylundecyl)-4-vinylpyridinium bromide was prepared. This polymer when spread on a water surface forms a stable condensed monolayer that was transferred onto a solid support to yield a Langmuir-Blodgett (LB) film. On UV light irradiation, the polymer LB film became insoluble in all organic solvents because of the formation of a two-dimensional photo-cross-linked polymer network. The cross-linking reaction was found to be caused by dimerization of acryloyl groups in the LB film. Fine negative resist patterns based on the insoluble two-dimensional polymer network can be drawn clearly after development of irradiated LB films with a solvent. The patterns of the cross-linked polymer LB films of various film thicknesses from bilayer to 200 layers were successfully achieved by using a conventional photolithographic technique. The bilayer patterns of cross-linked polymer LB films were observed using atomic force microscopy (AFM). These films had a thickness of 1.0 nm and a uniform surface.

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“…The master curves represent the frequency dependence at a constant temperature, which can cover a wide temperature range. The shift factor a T employed for the time-temperature superposition follows the WLF equation: where C 1 and C 2 are constants and T 0 is a reference temperature. As shown in Figure , the plot of −( T − T 0 )/log a T versus T − T 0 gave straight lines.…”

Section: Resultsmentioning

confidence: 99%

Structural Relaxation of Ultrathin Polymer Films Prepared by the Langmuir−Blodgett Technique: Characteristics of the Two-Dimensional System

Mabuchi¹,

Kawano²,

Ito³

et al. 1998

Macromolecules

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Thermal relaxation of ultrathin polymer films prepared by the Langmuir−Blodgett (LB) technique was studied by a comparison with a three-dimesional bulk system. Poly(vinyl alkanal acetal)s (PVAA) with different side chain lengths were synthesized and the thermal stability of their LB films was investigated by the energy-transfer phenomenon between fluorescence probes labeled to the polymer chains. The multilayer structure was irreversibly disordered and mixed by the thermal treatment. A close relationship was found between the glass-transition temperature (T g) of the polymer bulk and the temperature at which the layered structure of LB films started to disorder. Theoretical calculations based on Förster kinetics were applied to measure the diffusivity of polymer segments, which was successfully evaluated by assuming time-dependent Gaussian distributions of chromophores in the direction normal to the layer plane. The apparent activation energy ΔE a of the diffusion constant for the LB films, however, was much smaller than that for polymer bulk obtained by the viscoelastic measurement. It was concluded that the relaxation process of the ultrathin polymer films occurs by conformational changes from the two-dimensional nonequilibrium state given by the LB deposition. The confined form could be released by the local motion of the polymer segments under the heating to temperatures higher than T g.

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Photochemical Stabilization of Ultrathin Polymer Films Prepared by the Langmuir-Blodgett Technique

Cited by 10 publications

References 6 publications

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

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

Photopatterning Using a Cross-Linkable Polymer Langmuir−Blodgett Film

Structural Relaxation of Ultrathin Polymer Films Prepared by the Langmuir−Blodgett Technique: Characteristics of the Two-Dimensional System

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