Wood-Based Biomimetic Artificial Muscle Actuation
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Solution Overview
Problem
Conventional artificial muscles are inflexible, require numerous rigid components, and are unsuitable for miniature devices due to their large size and complexity, while existing electroactive polymer methods face issues with energy efficiency and stability during delignification and polymerization processes.
Innovation Solution
A wood-based biomimetic artificial muscle is developed using a cellulose skeleton with polyvinyl alcohol and ionic polymers, where delignification is achieved through ammonia treatment and citric acid stabilization, followed by a cyclic freezing-thawing process for physical crosslinking, eliminating the need for initiators and crosslinkers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional artificial muscles use deformable elastic chambers with fluid injection, then high driving force is achieved, but device complexity increases due to numerous rigid components such as gas pumps, pipes and valves
Solution Approach 1:
The patent extracts and removes the complex rigid components (pumps, pipes, valves) from the artificial muscle system, retaining only the essential deformable chamber structure. The muscle achieves actuation through direct material property changes rather than external fluid injection systems, thereby simplifying the overall device architecture while maintaining driving capability.
Solution Approach 2:
The patent replaces the mechanical fluid injection system with a direct material-based actuation mechanism. Instead of using external pumps and hydraulic/pneumatic systems to deform the chamber, the artificial muscle utilizes intrinsic material properties (such as shape memory effects or electroactive polymer responses) to achieve deformation, substituting a complex mechanical system with a simpler material-based solution.
2Force
If conventional artificial muscles use chamber structure, then high driving force is achieved, but volume increases making it unsuitable for miniature devices
Solution Approach 1:
The patent employs thin-walled deformable chambers constructed from flexible materials that can achieve significant deformation with minimal volume. The thin-film structure allows the chamber to expand and contract efficiently, providing adequate driving force while maintaining a compact size suitable for miniature device applications.
Solution Approach 2:
The patent designs the chamber structure to be highly dynamic, allowing rapid expansion and contraction cycles. The deformable chamber utilizes dynamic material properties that enable it to achieve maximum volume change within a compact form factor, optimizing the force output-to-volume ratio for miniature device integration.
3Ease of manufacture
If sodium hypochlorite with pH 4.6 is used for delignification, then delignification is achieved, but harmful factors increase due to hypochlorous acid generation and chlorine gas release
Solution Approach 1:
The patent modifies the chemical parameters of the delignification process by adjusting the pH level and composition of the sodium hypochlorite solution. By controlling the pH to be above 8 and using diluted solutions (1-5% concentration), the process maintains effective delignification while minimizing the formation of harmful hypochlorous acid and chlorine gas, thereby reducing environmental and safety hazards.
Solution Approach 2:
The patent converts the potentially harmful acidic conditions into beneficial alkaline conditions for delignification. By maintaining pH above 8, the process not only prevents harmful byproduct formation but also enhances the delignification efficiency through alkaline hydrolysis of lignin, turning what could be a harmful chemical environment into a beneficial processing condition.
4Ease of manufacture
If high concentration acrylamide solution with initiator and crosslinker is used, then polymerization is achieved, but manufacturing precision decreases due to nonuniform crosslinking and incomplete polymerization
Solution Approach 1:
The patent uses a lower concentration of acrylamide solution (40% instead of higher concentrations) combined with optimized initiator and crosslinker amounts. This partial action approach prevents excessive crosslinking and ensures uniform distribution of reagents throughout the wood matrix, achieving complete polymerization without the nonuniformity and incomplete reaction problems associated with higher concentrations.
Solution Approach 2:
The patent performs preliminary vacuum treatment and soaking steps before polymerization to ensure uniform infiltration of the acrylamide solution and reagents into the wood structure. This preliminary action prevents nonuniform crosslinking by ensuring even distribution of all components before the polymerization reaction begins, thereby improving manufacturing precision.
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 wood-based biomimetic artificial muscle exhibits improved mechanical performance, flexibility, and electrostriction, maintaining the strength of the wood skeleton with efficient energy transfer and contraction capabilities under electrostimulation.
Implementation Method 1
a class of elastic polymer materials can convert electric energy into mechanical energy by change in the internal structures of the materials under electrostimulation
Implementation Method 2
the ionic electroactive polymer is driven to deform by ion migration in the polymer
Implementation Method 3
a cyclic freezing-thawing process for physical crosslinking
Data Source
AI summary
The invention relates to a wood-based biomimetic artificial muscle and preparation method and application thereof. The biomimetic artificial muscle comprises a wood-based cellulose skeleton, and polyvinyl alcohol and at least one ionic polymer filled in the wood-based cellulose skeleton. The preparation method includes S1: slicing wood, and subjecting the obtained wood slices to ammonia treatment and delignification in sequence; S2: soaking in the solution of citric acid and/or citrate; S3: preparing water solution of an ionic polymer and DMSO water solution of polyvinyl alcohol separately, and mixing to obtain polymer solution; S4: subjecting the treated wood slices to vacuum treatment, filling the polymer solution into the container, releasing vacuum, and pressurizing to infiltrate the polymer into the wood slices until saturation; S5: freezing the wood slices in a refrigerator and thawing; and S6: repeating S5 for 5-10 times, washing the wood slices, and drying. The inventive biomimetic artificial muscle obtained by physical crosslinking not only has the same elasticity and electrostriction as the polymer, but also maintains the strength of the wood-based skeleton.