Thermo-Responsive Textile Coating for Adaptive Vapor Permeability
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Solution Overview
Problem
Conventional textiles and membranes exhibit inadequate water vapor flow at body temperature and above, leading to discomfort during physical activity, and have low mechanical strength due to dispersed hydrogel particles, which are not effectively responsive to ambient temperature and humidity changes.
Innovation Solution
A solid composite material comprising a structural polymer matrix and a thermo-responsive hydrogel, formed by cross-linking a cross-linkable compound with reactive moieties, creating interpenetrating matrices that provide enhanced mechanical strength and temperature-responsive water vapor permeability, allowing for low permeability at low temperatures and high permeability at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydrophobic membranes are used to provide breathable water-repellent layers, then water vapor permeability is improved at low temperatures, but water vapor flow becomes inadequate at body temperature and above
Solution Approach 1:
The patent applies dynamics by incorporating thermally-responsive hydrogel particles that dynamically alter the membrane's pore structure in response to temperature changes. At low temperatures, the hydrogel particles maintain a swollen state that allows water vapor passage, while at body temperature and above, they undergo phase transition to a collapsed state that opens up the pore structure for enhanced breathability and sweat evaporation.
Solution Approach 2:
The patent utilizes parameter changes by selecting hydrogel particles with specific lower critical solution temperatures (LCST) that trigger phase transitions at body temperature. This allows the membrane's permeability parameter to automatically adjust based on ambient temperature, providing low-temperature vapor permeability while enabling high-temperature breathability without external control mechanisms.
2Adaptability or versatility
If dispersed hydrogel particles are used in a binder matrix, then temperature-responsive water vapor flow is achieved, but mechanical strength is reduced
Solution Approach 1:
The patent applies composite materials by combining hydrophobic membrane base material with dispersed thermally-responsive hydrogel particles. This composite structure leverages the strength and water-repellent properties of the hydrophobic membrane while incorporating the temperature-responsive characteristics of the hydrogel particles, achieving both mechanical integrity and adaptive permeability.
Solution Approach 2:
The patent uses local quality by distributing thermally-responsive hydrogel particles selectively within specific regions or layers of the membrane structure. This allows the hydrophobic matrix to provide overall structural strength while the localized hydrogel particles provide temperature-responsive functionality where needed, optimizing both mechanical properties and adaptive behavior.
3Reliability
If the binder matrix is made hydrophilic to allow moisture passage, then water vapor flow is improved, but water repellency is reduced
Solution Approach 1:
The patent uses an intermediary approach by employing a hydrophobic binder matrix that does not inherently provide water vapor flow, but instead relies on the thermally-responsive hydrogel particles as mediators. These particles control moisture passage through their phase transitions, allowing the matrix to maintain hydrophobicity and water repellency while achieving vapor flow functionality through the hydrogel's temperature-dependent behavior.
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 composite material achieves improved comfort by maintaining impermeability to air and liquid at low temperatures while allowing vapor passage, and increasing permeability at higher temperatures to prevent sweat accumulation, while maintaining mechanical strength and responsiveness to environmental conditions.
Implementation Method 1
inducing the cross-linkable compound to cross-link by a first induction means whereby the thermo-responsive hydrogel is formed
Implementation Method 2
the hydrogel particles are present as a discontinuous dispersed solid phase in a continuous solid matrix... exhibiting expansion or contraction in response to a change in relative humidity and/or exposure to sweat
Implementation Method 3
provide a low permeability to water vapour at low temperatures and a high permeability to water vapour at high temperatures
Implementation Method 4
exhibiting expansion or contraction in response to a change in relative humidity and/or exposure to sweat
Data Source
AI summary
A method for preparing a solid composite material comprising a structural polymer matrix and a thermo-responsive hydrogel involvesforming a substantially homogeneous blend of a cross-linkable compound and monomer, oligomer or polymer particles in a blended aqueous liquid,inducing the cross-linkable compound to cross-link to form the thermo-responsive hydrogel andforming the structural polymer matrix from the structural polymer by a further induction means, wherein the resulting solid composite material provides a textile or membrane which presents a thermally insulating layer, through which air and/or liquid water cannot easily pass at low temperatures, but which also provides a more open structure at higher temperatures so that air and moisture vapor can pass through the textile or membrane.