Electrical-Field Alignment of Flexible Thermally Conductive Polymers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional thermally conductive materials are limited by low thermal conductivity, brittleness, and mechanical inflexibility, with existing methods unable to enhance thermal conductivity beyond 200°C and maintain mechanical flexibility, and there is a need for anisotropic polymers with adjustable molecular weight for improved thermal management.
Innovation Solution
The development of anisotropic thermally conductive polymers with dynamic molecular weight, achieved through the alignment of crystalline domains using electrical fields, and the use of reactive end groups to induce molecular weight growth and alignment, resulting in enhanced thermal conductivity along specific dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional polymers or composites are used for thermal management, then electrical insulation is achieved, but thermal conductivity remains below 0.5 W·m−1·K−1
Solution Approach 1:
The patent applies local quality by creating anisotropic thermal conductivity within the polymer structure. Crystalline domains are aligned in specific directions to provide high thermal conductivity pathways while the amorphous regions maintain electrical insulation. This directional organization allows different parts of the material to have different thermal conductivities, achieving high thermal performance in the alignment direction while preserving electrical insulation properties.
Solution Approach 2:
The patent creates a composite structure at the molecular level by combining crystalline domains (for thermal conduction) with amorphous polymer matrices (for electrical insulation). The crystalline regions are formed by aligning polymer chains through stretching or shear forces, creating a hybrid structure that simultaneously achieves high thermal conductivity and electrical insulation without requiring separate filler materials.
2Temperature
If metal heat spreaders are used to improve thermal conductivity, then thermal management efficiency increases, but mass increases significantly
Solution Approach 1:
The patent applies parameter changes by transforming the thermal conductivity parameter of the polymer through mechanical processing. By applying stretching or shear forces during processing, the polymer chains are aligned to create crystalline domains with enhanced thermal conductivity. This changes the thermal transport properties of the polymer from isotropic and low-conductivity to anisotropic and high-conductivity in the alignment direction, achieving metal-like thermal performance without the weight penalty.
3Temperature
If polymers filled with high-thermal-conductivity fillers are used, then thermal conductivity is enhanced, but mechanical flexibility is lost due to brittleness
Solution Approach 1:
The patent replaces the mechanical filler approach with a molecular-level structural organization. Instead of adding discrete filler particles that compromise flexibility, the patent uses mechanical forces (stretching, shear) during processing to align the polymer chains themselves, creating crystalline domains that provide thermal conduction pathways. This substitutes the need for external fillers with an intrinsic structural modification that preserves the polymer's flexibility while enhancing thermal conductivity.
4Temperature
If polyethylene is stretched and aligned at 90°C to achieve high thermal conductivity, then thermal conductivity is enhanced in the deformation direction, but the material cannot be taken above this temperature without losing properties
Solution Approach 1:
The patent applies preliminary action by establishing the crystalline domain alignment during the processing stage through stretching or shear forces. This alignment is locked in during manufacturing, creating a stable anisotropic structure that maintains thermal conductivity enhancement at higher operating temperatures. The alignment is performed preliminarily during processing rather than requiring continuous maintenance at low temperatures, enabling the material to retain its enhanced thermal properties across a broader temperature range.
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 polymers exhibit thermal conductivity greater than steel while maintaining mechanical flexibility, with reduced thermal expansion and phonon scattering, enabling efficient thermal management across arbitrary directions and thicknesses.
Implementation Method 1
exposing the thermotropic liquid-crystal oligomer to an electrical field, thereby aligning domains of the oligomer along a crystal axis
Implementation Method 2
applying a reactive end-group trigger to induce chemical bonding of the reactive end groups, thereby increasing the molecular weight of the aligned oligomer
Implementation Method 3
The polymers exhibit thermal conductivity greater than steel while maintaining mechanical flexibility, with reduced thermal expansion and phonon scattering, enabling efficient thermal management across arbitrary directions and thicknesses
Data Source
AI summary
Some variations provide an oligomer composition comprising: polarizable first thermotropic liquid-crystal oligomer molecules (preferably urethanes or ureas) containing first triggerable reactive end groups, wherein the first triggerable reactive end groups are selected from the group consisting of hydroxyl, isocyanate, blocked isocyanate, acrylate, epoxide, amine, vinyl, ester, thiol, conjugated diene, substituted alkene, furan, maleimide, anthracene, and combinations thereof, and wherein the polarizable first thermotropic liquid-crystal oligomer molecules are characterized by a weight-average molecular weight from about 200 g/mol to about 10,000 g/mol; optionally, a plurality of polarizable second thermotropic liquid-crystal oligomer molecules containing second triggerable reactive end groups, wherein the second triggerable reactive end groups are capable of reacting with the first triggerable reactive end groups; and optionally, a reactive coupling agent capable of reacting with the first triggerable reactive end groups. Methods are described for converting the oligomer composition into an anisotropic thermally conductive polymer. Many commercial uses are disclosed.