Liquid Polymer/Metallic Salt-Based Stretchable Strain Sensor to Evaluate Fruit Growth

Area of Science:

• Materials Science
• Biotechnology
• Sensor Technology

Background:

• Conventional fruit dimension measurement methods are bulky and difficult for continuous monitoring.
• Existing systems face challenges with precision and ease of use in agricultural applications.

Purpose of the Study:

• To develop an innovative, liquid-state stretchable strain sensor for precise fruit growth monitoring.
• To overcome the limitations of conventional measurement techniques in terms of bulkiness and continuous monitoring.

Main Methods:

• Incorporated poly(ethylene glycol) (PEG) and silver nitrate into a transparent polymer band.
• Optimized the ratio of poly(dimethylsiloxane) (PDMS) and Ecoflex (20:80) for desired mechanical properties.
• Investigated the correlation between strain and resistance of the PEG-silver nitrate composite sensor.

Main Results:

• Achieved high sensitivity and good repeatability with linear resistance changes (R² > 0.99) up to 30% strain.
• Demonstrated excellent sensor stability (1.7 to 3.9 kΩ/mm) when tested as a dendrometer on fruits.
• The sensor exhibited a balance of large strain, low stress, and reduced stickiness.

Conclusions:

• The developed liquid-state stretchable strain sensor offers a promising solution for precise, long-term fruit growth evaluation.
• This tunable elastic band sensor opens new avenues for versatile applications in agricultural monitoring.
• The sensor's performance validates its potential for non-invasive, continuous measurement of biological growth.