Page 101 - Read Online

Page 10 of 34 Xi et al. Soft Sci 2023;3:26 https://dx.doi.org/10.20517/ss.2023.13

Degradable materials
Degradable materials refer to materials that can be decomposed into simpler components over time through
biodegradation or other chemical or physical processes . Degradable materials have many potential
[98]
advantages, such as reducing waste and reducing environmental impact . Over time, degradable materials
[99]
can be decomposed into simpler components, thus reducing the impact on the environment. In some
[100]
applications, degradable materials are safer and healthier than non-degradable materials . For wearable
sensors, some sensors need to come into direct contact with the human body, so biosafety is highly valued.
Fortunately, most biodegradable materials have good biological safety characteristics due to their inherent
properties. Non-degradable materials, such as plastics, can last in the environment for hundreds of years,
causing problems such as garbage, pollution, and wildlife damage. Many degradable materials made from
renewable resources, such as plant starch or cellulose, can be grown and harvested on a sustainable basis .
[101]
This reduces the dependence on non-renewable resources used to produce many non-degradable materials,
such as fossil fuels. The use of degradable materials can promote the innovation of product design and
development, thus producing more sustainable and environmentally friendly new products and
[102]
applications . Bio-based plastics, such as starch-based plastics, polylactic acid (PLA), and
polyhydroxyalkanoate (PHA), have good plasticity and processability and can be made into products of
etc.
various shapes, sizes, Cellulose and its derivatives, such as cellulose acetate, cellulose nitrate, , have
etc.
good mechanical strength and heat resistance and can be used to make various materials and products.
etc.
Natural polymer materials, such as starch, chitosan (chitosan), gelatin, protein, , have good
biocompatibility and bioactivity and can be used in various applications in the medical field. As shown in
Figure 3C, Lan et al. reported a new type of advanced flexible ultra-soft elastic transparent material, which
provided a unique combination of scalability, extensibility, and enzymatic degradation . Molecular
[101]
weight, mechanical strength, and degradation rate can be easily adjusted. Based on these characteristics, a
self-powered touch sensor for touch sensing and non-contact proximity detection was manufactured. These
properties made the flexible electronic equipment degradable, making them more eco-friendly and
environmentally friendly. As shown in Figure 3D, Chen et al. prepared magnetic bacterial cellulose of
CoFe O and used it to prepare a new type of flexible, biodegradable, and self-powered electromagnetic
4
2
sensor . Magnetic CoFe O nanoparticles were synthesized in the network structure of degradable
[103]
4
2
bacterial cellulose, which can be completely degraded after 56 hours for flexible composite magnetic films.
The sensor had good sensing characteristics and stability. After being installed on the monitoring smart
sheath, it can monitor the motion signal and identify the motion state. As presented in Figure 3E, Gong
et al. developed a highly transparent, biocompatible, fully biodegradable, and flexible TENG for energy
[99]
collection and wireless sensing . They added glycerol and polyurethane to regenerate silk fibroin, which
greatly improved the mechanical flexibility of the silk fibroin membrane, constructed hollow silver
nanofibers on the silk membrane to form a breathable, stretchable, biocompatible, and degradable thin
layer, and was used as triboelectric electrodes. The sensor obtained can be used for touch/pressure
sensing artificial electronic skin and can also be used as a switch to control the IoT wirelessly.

Biodegradable green electronic materials are materials designed to naturally degrade in the environment,
which can reduce electronic waste and pollution. These materials are typically made of biodegradable
polymers, such as cellulose, chitosan, or PLA, which come from renewable resources and have a minimal
environmental impact . The combination of biodegradable green electronic materials and self-powered
[104]
sensor technology can generate widely applicable biodegradable self-powered sensors, such as monitoring
the health status of patients. There are several methods for manufacturing biodegradable self-powered
sensors. One method is to use materials such as cellulose or PLA as substrates for sensors and then combine
them with piezoelectric or thermoelectric power generation technology to generate energy. Another method
is to use biomaterials such as enzymes or deoxyribonucleic acid (DNA) as sensing elements and then
combine them with biodegradable materials to create fully biodegradable sensors.