Polymer Turgor Actuator With Permeable Confinement for Fast High Force
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Solution Overview
Problem
Existing soft actuators face limitations in generating large forces at fast transformation speeds due to low elastic modulus and slow solvent diffusion-based shrinkage/swelling, hindering practical applications.
Innovation Solution
A polymer-based turgor actuator is designed with a polymer network member confined by a permeable confinement member, allowing for high osmotic pressure generation and rapid swelling through osmosis or electroosmosis, with a permeable membrane having an elastic modulus of 1 MPa or more to maintain structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the polymer network is allowed to swell freely through osmosis, then the transformation speed is improved, but the generated force is insufficient due to low elastic modulus
Solution Approach 1:
A flexible confinement structure with elastic modulus of 1 MPa or more is introduced to surround the polymer network. This flexible shell provides mechanical support to generate sufficient force while maintaining liquid permeability to enable rapid swelling through osmosis, thus resolving the contradiction between transformation speed and generated force.
2Force
If the polymer network is confined in a small volume, then the generated force increases, but the transformation speed decreases due to limited solvent diffusion space
Solution Approach 1:
The confinement structure is designed with porous or mesh characteristics that maintain liquid permeability. This allows solvent to diffuse rapidly through the structure while the confined geometry provides sufficient mechanical constraint to generate high force, simultaneously improving both transformation speed and generated force.
3Force
If the polymer network is confined by a rigid structure, then the generated force increases, but the structure cannot maintain integrity under high osmotic pressure
Solution Approach 1:
The elastic modulus of the confinement structure is optimized to be 1 MPa or more, providing sufficient rigidity to maintain structural integrity under high osmotic pressure while remaining flexible enough to allow rapid swelling. This parameter optimization enables the structure to withstand high forces without failure.
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 actuator achieves high mechanical output performance, generating forces of several MPa without external power, enabling rapid transformation and easy control of force, speed, and rigidity, suitable for underwater and floating structures.
Implementation Method 1
The polymer member may be configured to absorb liquid and to swell through osmosis phenomenon or electroosmosis phenomenon.
Implementation Method 2
The polymer member may be configured to absorb liquid and to swell through osmosis phenomenon or electroosmosis phenomenon.
Data Source
AI summary
The present disclosure provides a polymer-based turgor actuator including a polymer network member (hereinafter, polymer member) capable of absorbing liquid and swelling, and a permeable confinement member configured to physically constrain the polymer member by confining it in an internal accommodation space and having liquid permeability, wherein an acceptable volume of the internal accommodation space of the permeable confinement member is smaller than the maximum swelling volume of the polymer member in the absence of the permeable confinement member.