Polyisopropylacrylamide Soft Actuator for Faster Water-Driven Force
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Solution Overview
Problem
Existing water responsive soft actuators suffer from low actuation force and slow actuation speed, limiting their practical application in soft robotics.
Innovation Solution
A water responsive soft actuator driven by polyisopropylacrylamide, which increases actuation force to MPa levels and actuation speed to 0.01-5 s−1 through controlled water absorption and release, using N-isopropylacrylamide crosslinking and external force deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If water responsive soft actuators are manufactured based on hydrogel and driven by swelling/expansion mitigation process, then they can operate in natural environment with minimal artificial intervention, but they exhibit low actuation force (about 10^-2 N) and slow actuation speed (about 10^-2 s^-1)
Solution Approach 1:
The patent changes the material parameter from conventional hydrogel to polyisopropylacrylamide, which has different water absorption characteristics. This material substitution enables the actuator to achieve high rigidity (MPa level) and fast actuation speed while maintaining water-based operation, resolving the contradiction between natural environment operation and actuation force
2Adaptability or versatility
If water responsive soft actuators are manufactured based on hydrogel and driven by swelling/expansion mitigation process, then they can operate in natural environment with minimal artificial intervention, but they exhibit slow actuation speed (about 10^-2 s^-1)
Solution Approach 1:
The patent changes the material parameter from conventional hydrogel to polyisopropylacrylamide, which has different water absorption characteristics. This material substitution enables the actuator to achieve fast actuation speed (0.01-5 s^-1) while maintaining water-based operation, resolving the contradiction between natural environment operation and actuation speed
3Force
If the soft actuator uses polyisopropylacrylamide with controlled water absorption, then it achieves high rigidity at MPa level and fast actuation speed, but it requires controlled crosslinking and deformation processes
Solution Approach 1:
The patent applies preliminary action by performing crosslinking of N-isopropylacrylamide before water absorption, and by pre-deforming the actuator in its elastically deformable state. These preliminary actions prepare the actuator structure to achieve high actuation force while maintaining a relatively simple overall process
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 soft actuator achieves high rigidity and fast actuation by absorbing and releasing small amounts of water, enabling effective control of actuation force and speed, overcoming practical limitations of typical soft robots.
Implementation Method 1
the water responsive soft actuator is driven by water absorption of polyisopropylacrylamide
Implementation Method 2
crosslinking N-isopropylacrylamide to make an object of a first shape including polyisopropylacrylamide
Implementation Method 3
allowing water to be absorbed into the object of the first shape to allow the object of the first shape to be in an elastically deformable state
Data Source
AI summary
The invention relates to a water responsive soft actuator using water responsive hydrogel whose volume hardly changes, and a method for driving the soft actuator. The water responsive soft actuator according to the invention includes polyisopropylacrylamide, and the polyisopropylacrylamide has an N-isopropylacrylamide monomer and water in a weight ratio of 87:13 to 95:5, wherein the water responsive soft actuator is driven by water absorption of the polyisopropylacrylamide.