Evaluation of Molecular Orientation in Aromatic Polyimide Films by FT-IR Reflection Absorption Spectroscopy

Iida, K.; Imamura, Yukihiro; Liao, Cheng-I; Nakamura, Shuhei; Sawa, Goro

doi:10.1295/polymj.28.352

Cited by 20 publications

(6 citation statements)

References 18 publications

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“…A new peak found centered at ca. 1858 cm -1 was assigned as characteristic asymmetric C=O stretching vibration of anhydride moiety [11]. These results also support the previously mentioned mechanism partly.…”

Section: Resultssupporting

confidence: 88%

40.4: New Photoalignment Polymeric Materials with Excellent Photosensitivity and Stability

Zhong

Lee

et al. 2004

Symp Digest of Tech Papers

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Novel soluble photoalignment materials with high photosensitivity and good thermal stability were synthesized by chloromethylation of 6FDA-ODA polyimide, and their photoalignment properties were investigated. The photosensitivity of 6FDA-ODA polyimide was improved greatly by the introduction of chloromethyl side group. The ECB LC cell made with photoaligned films could be stored at 85℃ for at least 14 days without deteriorating LC alignment. The irradiation of polarized UV light on the polymer surface induced thermally stable alignment of LC due to the surface anisotropy caused by photodecomposition of polyimide main chain.

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Section: Resultssupporting

confidence: 88%

40.4: New Photoalignment Polymeric Materials with Excellent Photosensitivity and Stability

Zhong

Lee

et al. 2004

Symp Digest of Tech Papers

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“…A higher temperature post-annealing (≥300°C) is sometimes carried out to complete the imidization reaction. The synthesis of polyimides (with thickness between a few 1 to 10 μm) has been successfully demonstrated by this method for PMDA/ODA [16][17][18][19] and other variants of polyimides. Polyimides synthesized by VDP generally have a low oxygen permeability in comparison with conventional spincoated versions and adhere relatively well to their substrate.…”

Section: Vapor-deposition Process (Vdp)mentioning

confidence: 99%

Polyimide in Electronics: Applications and Processability Overview

Diaham¹

2021

Polyimide for Electronic and Electrical Engineering Applications

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Polyimides are nowadays quite famous dielectrics and insulating materials widely used in electronics and electrical engineering applications from low voltage microelectronics up to high voltage engineering industry. They are well appreciated because of their excellent physical properties (i.e., thermal, electrical, and mechanical properties), as well as, their coating process ease either from a liquid or a gas phase. Consequently, polyimides appear in a various range of applications to efficiently separate metal levels or electrodes at different electrical potentials. This chapter intends to review the main chemical generalities of polyimides, the different monomer families, the coating and curing processes, and the main physical properties for electronic and high voltage industrial applications.

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“…Iida et al 6 developed a method for the quantitative evaluation of molecular orientation in organic films containing rigid parts using FT-IR spectroscopy. Polyimide has the imide ring as the rigid part, so this method was selected for quantitative evaluation of molecular orientation of the polyimide films.…”

Section: Effects Of Curing On Molecular Orientationmentioning

confidence: 99%

Effects of Thermal Curing on the Structure of Polyimide Film

Kim

Park

1998

Polym J

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ABSTRACT:The effects of thermal curing method on degree of imidization, molecular orientation, and chain ordering of the 4,4-oxydiphenylene pyromellitimide (PMDA--ODA) were investigated. Three different thermal curing methods were chosen in this study; two casts of polyamic acid on silicon wafer were isothermally cured at 200°C for 3 h (l-200) and 300°C for 3 h (l-300) respectively, and the other one was cured in step manner (S-300): I00°C for 1 h, 200°C for 1 h, and finally 300°C for I h. The degree of imidization was highest in the 1-300 and lowest in the S-300, demonstrating that the amount of solvent and degree of imidization at each stage of the curing cycles significantly affect the final degree of imidization. The degree of in-plane orientation was found highest for the S-300 and lowest for the 1-300. This suggests that the in-plane orientation decreases with increase of the chain immobilization. This chain ordering was found to be easily induced for the 1-300 among the three cured films. In the 1-300, the chains in the film are sparsely packed and ordering by the diffusion of polymer chians occurs most easily.KEY WORDS 4,4-Oxydiphenylene Pyromellitimide / Degree of Imidization / Molecular Orientation / Chain Ordering / In recent years, much attention has been directed to aromatic polyimide films, widely used as high-temperature insulators and dielectric coatings, adhesives, matrices, and alignment layer films for liquid crystal display. 1 • 2 The traditional synthetic route for these materials is two steps, the synthesis of poly(amic acid) (PAA) and subsequent thermal or chemical imidization (curing) of the PAA. 1 In preparation of the polyimide films, thermal imidization is generally used as the second step. Thermal imidization involves the simultaneous loss of solvent, cyclization of amic acid group to form imide, and both intra-and inter-molecular structure evolution. 3 • 7 -12 Regulation of the conditions on thermal imidization provides a wide spectrum of properties. Thus, understanding the effects of thermal curing method on the structure of the resulting polyimide film is very important to control the microstructure of the polyimide formed and to ensure final properties. However, a comparison of the degree of imidization, molecular orientation, and chain ordering among the polyimide films prepared by thermally different curring methods has not been made.This article studies the effects of thermal curing method on the structure of the polyimide films interfaced with silicon substrate. Three different curing methods were taken as follows; (i) isothermal curing at 200°C for 3 h (1-200), (ii) isothermal curing at 300°C for 3 h (1-300), and (iii) step curing (S-300) which consists of three steps: isothermal heating at 100°C for 1 h followed by isothermal heating at 200°C for 1 h, and then isothermal heating at 300°C for l h. EXPERIMENTAL MaterialsPyralin (Du Pont), a mixture of polyamic acid (4,4'-oxydiphenylene pyromellitamic acid), l-methyl-2-pyrrot To whom all correspondence should be addressed.lido...

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Evaluation of Molecular Orientation in Aromatic Polyimide Films by FT-IR Reflection Absorption Spectroscopy

Cited by 20 publications

References 18 publications

40.4: New Photoalignment Polymeric Materials with Excellent Photosensitivity and Stability

40.4: New Photoalignment Polymeric Materials with Excellent Photosensitivity and Stability

Polyimide in Electronics: Applications and Processability Overview

Effects of Thermal Curing on the Structure of Polyimide Film

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