Ionic Liquid Crystal Elastomer Actuation

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Solution Overview

Problem

Current ionic electroactive polymers (iEAPs) face limitations such as slow response times, the need for patterned electrodes to achieve complex shapes, and lack of multifunctionality, as well as requiring high electric fields for actuation, which are not suitable for low-voltage driven soft robotic actuators.

Innovation Solution

The development of ionic liquid crystal elastomer compositions that include a liquid crystal elastomer and an ionic liquid, allowing for actuation by low voltages and offering pre-programmable deformations, with alignment-dependent bending strains and dual thermal and electric actuation capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If ionic electroactive polymers (iEAPs) are used for actuation, then bending strain can be achieved, but the response time is slow

Engineering Contradiction:

Improveresponse timeVSAvoidactuation performance

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The patent combines liquid crystal elastomer (LCE) with ionic liquid (IL) to create a composite material that integrates the fast response of LCE with the ionic actuation mechanism of iEAPs. The LCE matrix provides rapid response to electric fields through director reorientation, while the ionic liquid enables ionic conduction and electrochemical actuation, achieving both fast response and reliable bending strain.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent modifies the actuation mechanism by changing the material parameters - specifically incorporating ionic liquid into LCE to enable ionic conduction. This parameter change allows the material to respond to low-frequency and DC electric fields that would not effectively actuate conventional LCEs, thereby improving response time while maintaining actuation performance.

Inventive Principle:

Principle #35Parameter changes

2Shape

If patterned electrodes are used to achieve complex shapes, then shape control is improved, but device complexity increases

Engineering Contradiction:

Improveshape controlVSAvoidelectrode pattern complexity

Core Design Contradiction:

ShapeVSDevice complexity

Solution Approach 1:

The patent incorporates the alignment of liquid crystal molecules during the material fabrication process to pre-program the desired shape changes. By controlling the molecular alignment in the LCE matrix before final device assembly, complex shapes and deformation patterns can be achieved without requiring complex patterned electrodes, thereby reducing device complexity while maintaining shape control.

Inventive Principle:

Principle #10Preliminary action

3Force

If high electric fields are used for actuation, then bending strain is improved, but energy consumption increases

Engineering Contradiction:

Improvebending strainVSAvoidenergy consumption

Core Design Contradiction:

ForceVSUse of energy by moving object

Solution Approach 1:

The patent creates a multi-functional material that responds to multiple types of electric fields - both high-frequency AC fields (for fast response through director reorientation) and low-frequency/DC fields (for sustained actuation through ionic conduction). This universality allows the material to achieve bending strain under various electric field conditions, reducing the need for consistently high electric fields and thereby lowering energy consumption.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 ionic liquid crystal elastomers achieve bending strains comparable to iEAPs at low voltages, with improved actuation performance, pre-programmable patterns, and dual actuation capabilities, suitable for biomedical and portable soft robotics applications.

Implementation Method 1

even weak low frequency or DC electric fields cause drift of ions in opposite directions, leading to an expansion (compression) at the side where the larger (smaller) ions move

Methodology Applied

Scientific EffectIon drift: Electrophoresis

Implementation Method 2

Especially large strain (up to 4%) can be achieved via the electroclinic effect at electric fields E2), which requires a very large electric field (E>30 V/μm)

Methodology Applied

Scientific EffectElectroclinic effect: Electro-Optic Effects

Implementation Method 3

One possibility to reach large electric field induced mechanical deformations is the use of dielectric heating that converts electric energy to heat and causes a deformation by reducing the director order

Methodology Applied

Scientific EffectDielectric heating: Dielectric Heating

Implementation Method 4

liquid crystal elastomers (LCEs), which combine the orientational order of liquid crystal mesogens with the soft elasticity of polymer networks, can produce extremely sensitive deformations in response to diverse external stimuli

Methodology Applied

Scientific EffectLiquid crystal elasticity: Liquid Crystals

Data Source

PatentUS11814562B2Electro-responsive ionic liquid crystal elastomer

Publication Date: 2023.11.14 KENT STATE UNIV

AI summary

An ionic liquid crystal elastomer composition includes a liquid crystal elastomer; and an ionic liquid.