Polyimide Film Diamine Structure for Thermal Stability
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Solution Overview
Problem
Existing polyimide films used in flexible devices face challenges with thermal stability and mechanical properties, particularly during high-temperature processes like those in OLED manufacturing, where thermal decomposition can occur.
Innovation Solution
A novel diamine compound with a specific structure, featuring diphenyl sulfide bonded to phenyl rings via an amide bond, is used to create a polyimide precursor. This precursor is then processed to form a polyimide film with improved thermal and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional polyimide films are used in high-temperature OLED manufacturing processes, then the device can be manufactured, but thermal decomposition by hydrolysis occurs at temperatures close to 500°C
Solution Approach 1:
The patent modifies the chemical structure of diamine compounds by introducing specific substituents (fluoro, cyano, alkyl, aryl groups) at controlled positions and ratios to alter the thermal and mechanical properties of the resulting polyimide film, achieving both high heat resistance and thermal stability
Solution Approach 2:
The patent creates composite polyimide structures by combining rigid aromatic rings with flexible aliphatic chains and various functional groups (amide, ester, ether) in a single polymer chain, achieving a balance between thermal stability and mechanical properties
2Weight of moving object
If polyimide film is made thinner for flexible devices, then flexibility and lightness are improved, but mechanical strength and barrier properties deteriorate
Solution Approach 1:
The patent introduces different functional groups at specific positions on the diamine molecule (para, meta, ortho positions) to create localized regions with different properties - rigid aromatic regions for strength and flexible aliphatic regions for flexibility, achieving both thin-film flexibility and mechanical strength
Solution Approach 2:
The patent incorporates flexible chains and rotatable bonds into the polyimide structure, allowing the polymer chains to adapt and absorb stress dynamically, maintaining mechanical strength even in thin films
3Strength
If aromatic polyimide is used to achieve excellent mechanical properties and electrical insulation, then performance is improved, but synthesis complexity and manufacturing difficulty increase
Solution Approach 1:
The patent divides the complex diamine structure into modular segments (aromatic rings, aliphatic chains, functional groups) that can be independently synthesized and then combined through well-established polymerization reactions, simplifying the overall manufacturing process while maintaining excellent mechanical properties
Data Source
AI summary
Disclosed is a novel diamine compound comprising a structure in which diphenyl sulfide in a molecule is bonded through an amide bond to a phenyl ring substituted with an amine group. A polyimide film prepared by polymerizing the novel diamine compound exhibits improved mechanical and thermal properties and an enhanced refractive index.