Polyelectrolyte Polymer Thermal Conductivity via Chain Extension
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Solution Overview
Problem
Bulk polymers exhibit low thermal conductivity due to entangled structures with inefficient packing of curvilinear chains, leading to challenges in heat dissipation in electronic devices, and existing methods to enhance thermal conductivity often result in undesirable optical, electrical, or cost-related issues.
Innovation Solution
Contacting a bulk polyelectrolyte polymer with an aqueous liquid at specific pH to ionize pendant groups, extending the polymer chains into an isotropic non-globular conformation, thereby increasing thermal conductivity without the need for high-volume fillers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If bulk polymer is used, then ease of manufacture and processability are maintained, but thermal conductivity remains low
Solution Approach 1:
The patent changes the conformational parameter of polymer chains from coiled/entangled to extended linear morphology through uniaxial extension processing. This parameter change transforms the thermal transport properties while maintaining polymer processability, achieving thermal conductivity enhancement without requiring filler additives.
2Temperature
If high-κ fillers are blended to enhance thermal conductivity, then thermal conductivity increases, but optical properties deteriorate, weight increases, cost increases, and processability decreases
Solution Approach 1:
The patent extracts and eliminates the need for high-κ filler materials (metal particles, ceramic particles, carbon nanotubes, graphene) by achieving high thermal conductivity through pure polymer chain extension. This removes the harmful effects of fillers including deteriorated optical properties, increased weight, high cost, and loss of processability.
3Temperature
If high-κ fillers are blended to enhance thermal conductivity, then thermal conductivity increases, but weight increases
Solution Approach 1:
The patent removes the need for heavy filler materials by achieving thermal conductivity enhancement through molecular chain extension of the polymer itself. This extracts the weight penalty associated with metal, ceramic, carbon nanotube, or graphene fillers while maintaining the lightweight advantage of polymers.
4Temperature
If high-κ fillers are blended to enhance thermal conductivity, then thermal conductivity increases, but cost increases
Solution Approach 1:
The patent eliminates expensive filler materials (metal particles, ceramic particles, carbon nanotubes, graphene) and achieves thermal conductivity enhancement through simple uniaxial extension processing of the polymer. This extracts the high cost associated with filler materials while maintaining cost-effective polymer processing.
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
The method significantly enhances thermal conductivity of bulk polymers by up to four times, achieving values greater than 0.6 W/m·K, while maintaining the benefits of polymer processability and reducing costs associated with filler materials.
Implementation Method 1
contacting a bulk polyelectrolyte polymer with an aqueous liquid having a pH that ionizes the pendant group
Implementation Method 2
ionizes the pendant group and isotropically extends the polyelectrolyte polymer to an extended non-globular chain conformation
Implementation Method 3
The polyelectrolyte polymer so treated thus exhibits a thermal conductivity of greater than or equal to about 0.6 W/m·K
Data Source
AI summary
Methods of increasing thermal conductivity of a bulk polymer are provided. The methods include contacting a bulk polyelectrolyte polymer comprising an ionizable repeating pendant group with an aqueous liquid having a pH that ionizes the pendant group and isotropically extend the polyelectrolyte polymer to an extended non-globular chain conformation. The polyelectrolyte polymer so treated thus exhibits a thermal conductivity of greater than or equal to about 0.6 W/m·K and optionally greater than or equal to about 1 W/m·K. In other aspects, the present disclosure provides a high thermal conductivity material comprising a bulk polyelectrolyte polymer bearing a repeating charged group and having an extended non-globular chain conformation and that exhibits a thermal conductivity of greater than or equal to about 0.6 W/m·K and optionally greater than or equal to about 1 W/m·K. The high thermal conductivity material may be used in electronic devices, including as housings/encapsulation and thermal interfaces.