(Meth)acrylated Hyperbranched Polymers for OLED Encapsulation
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Solution Overview
Problem
There is a need for new materials that can be used in the manufacture of OLED thin film encapsulation layers, particularly materials that are easily adjustable to achieve a balance of properties such as low viscosity, solvent-free, high glass transition temperature, and etch resistance.
Innovation Solution
The development of (meth)acrylated hyperbranched polymers consisting of C, H, Si, optionally O, and optionally F atoms, with end groups comprising (meth)acryloyloxy groups, which are formed through AWBx polymerization and endcapping with primary alkenyl (meth)acrylates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional materials are used for OLED thin film encapsulation, then the material must have high glass transition temperature and etch resistance, but the viscosity becomes too high for inkjet printing
Solution Approach 1:
The patent changes the molecular architecture parameters by using hyperbranched polymer structures with controlled branching degrees and functional group densities. This allows adjustment of viscosity and Tg independently through parameter optimization of the polymer architecture rather than changing basic material composition
Solution Approach 2:
The patent creates composite encapsulation systems by combining hyperbranched polymers with specific functional groups (silane, vinyl, methacrylate) that provide both low viscosity and high Tg properties, achieving a synergistic effect where the composite structure delivers multiple desirable properties simultaneously
2Device complexity
If the material is made solvent-free to simplify the composition, then the viscosity control becomes more difficult, but adding solvent increases the complexity of the composition
Solution Approach 1:
The patent employs self-adjusting polymer architectures where the hyperbranched structure inherently provides the desired viscosity and flow characteristics without requiring external solvents or additives. The polymer itself serves the dual function of providing both low viscosity for printing and high Tg for stability
Solution Approach 2:
The patent uses parameter optimization of the hyperbranched polymer structure (branching degree, molecular weight distribution, functional group concentration) to precisely control viscosity and other properties without introducing solvents, achieving solvent-free formulations with optimized rheological behavior
3Reliability
If the glass transition temperature is increased for improved aging performance, then the material becomes more rigid and difficult to process, but lowering Tg improves processability
Solution Approach 1:
The patent segments the polymer structure into distinct functional regions within the hyperbranched architecture, separating the rigid backbone segments (providing high Tg) from the flexible side branches and end groups (providing low viscosity). This segmentation allows independent optimization of processing and performance properties
Solution Approach 2:
The patent optimizes multiple parameters simultaneously including branching degree, monomer composition ratios, and functional group distribution to achieve the desired balance between Tg and viscosity. By changing architectural parameters rather than simple composition, both properties can be optimized together
4Reliability
If the material is designed to be etch-resistant for plasma deposition, then the composition becomes more complex, but simplifying the composition reduces etch resistance
Solution Approach 1:
The patent designs hyperbranched polymer structures where the same basic architectural features (branching, functional group distribution, molecular weight control) simultaneously provide multiple functions: low viscosity for printing, high Tg for stability, and etch resistance for plasma processing. One structural approach delivers multiple protective functions
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
These materials provide a balance of properties necessary for OLED thin film encapsulation, including low viscosity for inkjet printing, high glass transition temperature for long-term aging performance, and etch resistance, while being solvent-free and easily adjustable.
Implementation Method 1
a curable composition comprising: a (meth)acrylatedhyperbranched polymer according to the present disclosure; at least one free-radically polymerizable monomer having at least one (meth)acryloyloxy groups; and an effective amount of a free-radical initiator for curing the curable composition
Implementation Method 2
at least one hydrosilylation reaction catalyst
Data Source
AI summary
A (meth)acrylated hyperbranched polymer consists of C, H, Si, optionally O, and optionally F atoms. The (meth)acrylated hyperbranched polymer comprises end groups, and at least some of the end groups comprise (meth)acryloyloxy groups. A method of making and a curable composition including the (meth)acrylated hyperbranched polymer are also disclosed. An electronic device includes an at least partially cured form of curable composition.