Polymer Thermal Switch Without Moving Parts
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Solution Overview
Problem
Existing thermal switch devices require complex structures with mobile elements and are costly to produce, lacking flexibility and reliability, and often require high voltage pulses to change conductivity.
Innovation Solution
A thermal switch device formed from a polymer composition comprising 50-99.9% amorphous or semi-crystalline polymers and 0.1-50% conductive materials, with a surface resistance that decreases by at least 10 times when exposed to specific temperature ranges, allowing for flexible, reliable, and cost-effective production without moving parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thermoresponsive polymer is used to create a thermal switch, then the device can detect high temperature and send an electrical signal, but the structure becomes complex with mobile elements
Solution Approach 1:
The patent extracts the mobile elements from the thermal switch structure, leaving only fixed components. The conductive polymer layer itself performs the switching function without requiring moving parts, thereby simplifying the overall structure while maintaining thermal detection capability.
Solution Approach 2:
The patent replaces mechanical/mobile elements with an electrical/conductive polymer-based system. The conductivity change of the polymer layer in response to temperature replaces the need for mechanical movement,从而实现 a solid-state thermal switch without moving parts.
2Ease of operation
If a conductive organic polymer layer is used, then current conduction can be switched between high and low conductivity states, but high voltage pulses are required to change conductivity
Solution Approach 1:
The patent changes the operational parameter from voltage-controlled switching to temperature-controlled switching. The conductive polymer layer's conductivity is modulated by temperature changes rather than high voltage pulses, making the device more energy-efficient and suitable for thermal sensing applications.
3Reliability
If complex structures with mobile elements are used, then thermal switch functionality is achieved, but production costs increase
Solution Approach 1:
By removing mobile elements and complex structures, the patent simplifies the manufacturing process. The thermal switch is realized through a simple layered structure with a conductive polymer layer between two electrodes, significantly reducing production complexity and cost.
4Reliability
If mobile elements are incorporated, then thermal switching is possible, but device flexibility is reduced
Solution Approach 1:
The patent replaces mechanical mobile elements with a flexible conductive polymer layer that can be integrated into various shapes and configurations. This solid-state approach enables device flexibility while maintaining thermal switching functionality.
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 device effectively detects high temperatures and switches conductivity without complex structures, enabling flexible and reliable operation with low production costs, and maintains thermal conductivity regardless of electrical changes.
Implementation Method 1
the change of conductivity of the organic polymer layer is the result of a high voltage pulse passed between the two conductors
Implementation Method 2
a thermoresponsive polymer that is in an expanded volume state at ambient temperature and in a contracted volume state at a defined higher temperature
Implementation Method 3
The experimental conductivity was found to obey a percolation like power law with a relatively low percolation threshold
Implementation Method 4
Ounaies et al in 'Electrical properties of single wall carbon nanotube reinforced polyimide composites' Composites Science and Technology 63 (2003) 637-1646
Data Source
AI summary
The present invention relates to an article suitable to act as a thermal switch device, the article having a surface resistance of more than 105 ohms and formed from a polymer composition comprising from 50 to 99.9 wt% relative to the total weight of the polymer composition, of a polymer being selected from an amorphous polymer having a glass transition temperature Tg, a semi-crystalline polymer having a melting temperature Tm or a mixture thereof, and from 0.1 to 50 wt% relative to the total weight of the polymer composition, of a conductive material, wherein the surface resistance of the article is divided by at least 10, preferably by at least 100, when said article is submitted for a determined period of time of less than 5 minutes to a temperature of switch i) ranging from Tg + 10 °C to Tg + 250 °C if the polymer composition comprises an amorphous polymer, or ii) ranging from Tm – 80 °C to Tm + 250 °C if the polymer composition comprises a semi-crystalline polymer.