REVEALing complex strain patterns and dangerous loads using cholesteric liquid crystal elastomers

Introduction

The Internet of Things (IoT), Industry 4.0, and the increased availability and performance of sensors have led to new generations of ‘smart’ products that can communicate real-time status information. This advancement improves energy balance, increases safety, and opens up better, more seamless experiences for consumers.

Importance of Mechanical Sensors

Mechanical sensors—often measuring strain—are key components in many scenarios. However, current technology typically employs point-based or one-dimensional (1D) strain sensors of resistive, piezoelectric, or optical fiber type. These sensors have low spatial resolution (one sensor, one value), which gives limited information about complex deformations and may even miss dangerous strains slightly away from the sensor.

Need for Advanced Solutions

There is thus a need for new solutions that offer 2D distributed strain sensing with high resolution. We recently proposed two new concepts for non-electronic strain sensing, both based on the mechanochromic response of Cholesteric Liquid Crystal Elastomers (CLCEs), which change color in response to mechanical deformation.

Value Proposition of REVEAL

The value proposition of REVEAL comprises:

1. Simple and scalable procedures for making CLCE sheets of large size.
2. Production of fibers of arbitrary length.
3. Excellent local mechanochromic response (from red to violet) upon strains of up to 200%.

Project Goals

Within REVEAL, we will produce CLCE sheets and fibers and assess their application potential in various fields, including:

• Structural health monitoring of the built environment.
• Smart clothing.
• Sports gear.

Challenges to Address

The challenges we wish to take on in REVEAL are:

1. Ensuring consistent and tunable relaxed color with sufficient time stability of our CLCE sheets and fibers.
2. Allowing adjustable and well-defined diameter of the CLCE fibers.
3. Reducing tackiness of the fibers, thus enabling easy manipulation and processability at large scale.
4. Ensuring strong full-area bonding to each relevant target surface of the CLCE sheets.
5. Assessing the usefulness in four specific target applications, two for each CLCE type.