3D Nanoporous Solid Structure for Phonon Thermal Insulation
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Solution Overview
Problem
Current thermal insulation materials, including porous structures and phononic crystal structures, have limitations in maximizing thermal insulation performance, particularly in reducing thermal conductivity effectively.
Innovation Solution
A solid material with a three-dimensional structure featuring recesses and a solid portion between them, where the minimum size of the solid portion is less than or equal to 100 nm and has an elastic modulus of 80% or less than that of a reference sample, effectively adjusting thermal conductivity by interacting with phonons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a porous structure with micrometer-sized pores is used for thermal insulation, then thermal insulation performance increases with higher porosity, but the thermal conductivity reduction is limited compared to nanoscale structures
Solution Approach 1:
The patent implements a hierarchical porous structure where nanoscale pores (1-100 nm) are nested within micrometer-sized pores (1-1000 μm), creating a multi-scale porous network. This nested configuration allows phonons to be scattered at multiple length scales, significantly reducing thermal conductivity while maintaining manageable structural complexity through systematic design
Solution Approach 2:
The patent transitions from conventional two-dimensional phononic crystal structures to three-dimensional hierarchical porous structures with pores distributed across multiple size dimensions. This dimensional expansion enables phonon scattering in multiple spatial scales simultaneously, achieving superior thermal insulation performance that cannot be obtained with single-scale structures
2Loss of energy
If phononic crystal structures with through-holes are formed to reduce thermal conductivity, then thermal insulation performance improves, but mechanical strength decreases due to the periodic through-hole array
Solution Approach 1:
The patent applies local quality by creating regions with different pore densities and sizes within the solid material. The hierarchical porous structure features varying porosity levels at different locations and scales, allowing optimal balance between thermal insulation performance and mechanical strength in different regions of the material
Solution Approach 2:
The patent creates a composite structure combining solid matrix material with hierarchical porous networks containing pores at multiple size scales. This composite configuration integrates the thermal insulation benefits of porous structures with the mechanical strength of the solid matrix, achieving superior overall performance
3Loss of energy
If the solid portion size between recesses is reduced to ≤100 nm, then phonon interaction increases and thermal conductivity decreases, but the elastic modulus and mechanical properties deteriorate
Solution Approach 1:
The patent segments the solid material into a hierarchical porous structure with recesses and solid portions at multiple size scales. The nanoscale solid portions (≤100 nm) are strategically distributed within a larger micrometer-scale porous framework, allowing phonon scattering at nanoscale interfaces while the micrometer-scale structure provides mechanical support and maintains overall elastic modulus
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
This configuration significantly enhances thermal insulation performance by reducing thermal conductivity and mechanical strength, offering high thermal insulation capabilities.
Implementation Method 1
a three-dimensional structure including recesses and a solid portion formed between the recesses, the three-dimensional structure adjusting a thermal conductivity of the solid material by interaction with phonons
Data Source
AI summary
A solid material includes a three-dimensional structure including recesses and a solid portion formed between the recesses, the three-dimensional structure adjusting a thermal conductivity of the solid material by interaction with phonons, wherein a minimum size of the solid portion between the recesses adjacent to each other in plan view of the three-dimensional structure is smaller than or equal to 100 nm, and the solid portion includes a region with a Young's modulus being smaller than or equal to 80% of a Young's modulus of a reference sample that is fabricated by using the same type of material as a material of the solid portion without forming any recesses.