Optical Second Harmonic Generation Analysis of Unrubbed Polyimide Surfaces as a Function of the Content of Steroidal Structure Side Chains

Trinh, Nguyen Thi Tuyet; Yu, Sheng; Asakura, Shinya; Hien, Khuat Thi Thu; Mizutani, Goro; Murakami, Yoshitaka; Okada, Takashi

doi:10.1380/ejssnt.2020.175

Cited by 3 publications

(1 citation statement)

References 10 publications

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“…The terminal isopropyl group in the side-chain of the polyimide containing steroidal structure as shown in Figure 1 is pointing toward the air side and the average tilt angle of the methyl group adjacent to the steroidal structure is 40 ± 10 in the rubbing direction. Analyzing the SHG response of the polyimide containing steroidal structure, we also figured out that both the polyimide side chains and the main chains contribute to this response [18].…”

Section: Introductionmentioning

confidence: 99%

Detection of Surface Modification of Polyimide Containing Steroidal Structure as a Function of Storage Time Using Second-Order Nonlinear Optical Spectroscopy

Nguyen,

Du,

Khuat

et al. 2023

e-J. Surf. Sci. Nanotechnol.

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The modification of a polyimide surface containing a 30% fraction of steroidal structure was studied as a function of storage time by vibrational sum frequency generation (SFG) spectroscopy and optical second-harmonic generation (SHG). The variation of the symmetric and anti-symmetric stretching modes of the CH 3 isopropyl group at the end of the side chain of the rubbed polyimide was detected in the SFG spectra after a 3-month storage time in a practical environment. It suggests that the isopropyl group might be reoriented. On the other hand, the SHG response of the same sample showed an insignificant storage-time dependence. As a result, the phenyl rings of the polyimide are judged to be unmodified after long-term storage time. The change is suggested to occur for two main reasons. One is the interaction between the polyimide polymers and the ambient water molecules. The other is the adsorption of unknown organic molecules on the polyimide surface.

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Section: Introductionmentioning

confidence: 99%

Detection of Surface Modification of Polyimide Containing Steroidal Structure as a Function of Storage Time Using Second-Order Nonlinear Optical Spectroscopy

Nguyen,

Du,

Khuat

et al. 2023

e-J. Surf. Sci. Nanotechnol.

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Study of the molecular orientation of steroidal side chains at polyimide surfaces using sum frequency generation vibrational spectroscopy

Nguyen

Khuat

Asakura

et al. 2021

The Journal of Chemical Physics

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The molecular orientation of steroidal side chains at rubbed polyimide (PI) surfaces is studied by sum frequency generation (SFG) vibrational spectroscopy. The main objective is to find a correlation between the molecular structure of the PI film and the liquid crystal alignment on the polymer. Analysis of the SFG spectra shows that rubbing of the polymer film appears to cause conformational changes in the methyl group of the polymer side chain near the steroidal structure. However, rubbing does not significantly influence the orientation of the isopropyl group at the end of the polymer side chain. This shows that the liquid crystal alignment is not correlated with the orientation of the isopropyl group.

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Detection of surface modification of polyimide containing steroidal structure as a function of storage time using second- order nonlinear optical spectroscopy

Nguyen

Khuat

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

The modification of a polyimide surface containing a 30% fraction of steroidal structure was studied as a function of storage time by vibrational sum frequency generation (SFG) spectroscopy and optical second-harmonic generation (SHG). The variation of the symmetric and anti-symmetric stretching modes of the CH3 isopropyl group at the end of the side chain of the rubbed polyimide was detected in the SFG spectra after 3 months storage time in a practical environment. It suggests that the isopropyl group might be reoriented. On the other hand, the SHG response of the same sample showed an insignificant storage-time dependence. As a result, the phenyl rings of the polyimide are judged to be unmodified after long-term storage time. The change is suggested to occur for two main reasons. One is the interaction between the polyimide polymers and the ambient water molecules. The other is the adsorption of unknown organic molecules on the polyimide surface.

show abstract

Optical Second Harmonic Generation Analysis of Unrubbed Polyimide Surfaces as a Function of the Content of Steroidal Structure Side Chains

Cited by 3 publications

References 10 publications

Detection of Surface Modification of Polyimide Containing Steroidal Structure as a Function of Storage Time Using Second-Order Nonlinear Optical Spectroscopy

Detection of Surface Modification of Polyimide Containing Steroidal Structure as a Function of Storage Time Using Second-Order Nonlinear Optical Spectroscopy

Study of the molecular orientation of steroidal side chains at polyimide surfaces using sum frequency generation vibrational spectroscopy

Detection of surface modification of polyimide containing steroidal structure as a function of storage time using second- order nonlinear optical spectroscopy

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