Beaded Core-Shell Fibers for Phase-Change Thermoregulation
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Solution Overview
Problem
Existing textile materials fail to efficiently regulate body temperature in varying environmental conditions, leading to discomfort and increased energy consumption for heating and cooling, and conventional electrospinning methods struggle with dissolving cellulose for durable thermoregulating fibers.
Innovation Solution
A coaxial electrospinning process using room temperature ionic liquids to dissolve cellulose and phase-change materials (PCMs) forms microfibers with a beaded structure, where cellulose forms a hydrophilic shell and PCMs like coconut oil provide thermoregulation by absorbing or releasing heat, with a melting temperature range of 20-25°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional electrospinning uses volatile solvents to dissolve cellulose, then the fiber formation process is simplified, but the durability and thermal stability of the resulting fibers deteriorate
Solution Approach 1:
The patent changes the solvent parameter from volatile organic solvents to non-volatile ionic liquids, fundamentally altering the dissolution conditions. This parameter change enables cellulose dissolution while eliminating the need for high-temperature evaporation, thereby improving fiber durability and thermal stability without sacrificing the electrospinning processability.
Solution Approach 2:
The patent introduces ionic liquids as an intermediary substance that mediates between cellulose and the electrospinning process. The ionic liquids serve as a non-volatile solvent that dissolves cellulose and can be removed through water washing rather than evaporation, enabling durable fiber formation while maintaining ease of manufacture.
2Adaptability or versatility
If phase changing materials are incorporated into textile fibers to regulate temperature, then thermoregulating properties are improved, but the complexity of fiber fabrication increases
Solution Approach 1:
The patent merges the phase changing material (PCM) incorporation step with the electrospinning fiber formation process itself. By feeding PCM along with the cellulose solution through the electrospinning apparatus, the patent combines two functions (fiber formation and PCM incorporation) into a single process, thereby achieving thermoregulating properties without significantly increasing fabrication complexity.
Solution Approach 2:
The patent segments the fiber structure into a core-shell configuration where the PCM is contained within a cellulose shell. This segmentation allows the PCM to be protected and positioned precisely within the fiber, enabling effective thermoregulation while simplifying the fabrication process compared to attempting to integrate PCM throughout the entire fiber structure.
3Reliability
If cellulose is dissolved in room temperature ionic liquids for electrospinning, then the durability of thermoregulating fibers is improved, but the cost and availability of solvents worsen
Solution Approach 1:
The patent employs a solvent recovery approach where the ionic liquid solvent is not consumed but can be recovered and reused. After the electrospinning process, the ionic liquid can be separated from the fiber product through water washing and reused in subsequent batches, thereby reducing the need for continuous purchase of expensive ionic liquids while maintaining fiber durability.
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 microfibers effectively maintain a stable temperature range by absorbing heat when warm and releasing it when cold, reducing the need for heating and cooling, and are sustainable and durable, suitable for textiles and insulation.
Implementation Method 1
a class of non-volatile, hydrogen-bond-breaking solvents known commonly as room temperature ionic liquids (RTILs) readily dissolve cellulose
Implementation Method 2
PCMs have the capability to store and release latent heat energy as they undergo phase changes while keeping their temperature constant
Implementation Method 3
PCMs have the capability to store and release latent heat energy as they undergo phase changes
Implementation Method 4
Electrospinning is a fiber fabrication technique that was invented nearly a century ago
Implementation Method 5
Cellulose, a linear polysaccharide with an extensive hydrogen-bonding network, possesses excellent thermal and mechanical properties
Implementation Method 6
the method includes drying the microfiber via freeze-drying, air drying, or combinations thereof
Data Source
AI summary
A network of microfibers are fabricated with a core-shell construction from sustainable materials, where the core includes a phase-change material, such as coconut oil, and the shell includes a biomass, such as cellulose. The microfibers are made via a wet-wet electrospinning process utilizing a coaxial spinneret with an inner conduit and an outer conduit. The biomass and the phase-change material are coaxially extruded into a coagulation bath including a mixture of ethanol and water. The collected microfibers exhibit a beaded structure of PCM aggregates and biomass connecting regions between the aggregates and are effective to aid in the thermoregulation of the immediate environment surrounding the network. The microfibers are suitable for use in a variety of sustainable products such as wearable thermoregulating textiles, wall/ceiling panels, insulation, packaging material, and more.