Page 195 - Read Online

Page 10 of 12 Wu et al. Soft Sci 2023;3:35 https://dx.doi.org/10.20517/ss.2023.26

and read in the form of voltage changes, which were used as signals to control the right machine hand to
make symmetrical gestures [Figure 4D]. Experimental results show that the strain-sensing glove can easily
realize the symmetrical manipulation of the machine hand due to its good compliance and sensitivity.

Discussion
In terms of the cost of the strain-sensing glove for daily life, several factors contribute to its affordability.
The disposable nitrile gloves used as substrates are inexpensive. Additionally, the encapsulation material
and PVA, which serve as binders, are also very cheap and used in minimal quantities. The commercial
industrial-grade liquid metal, along with its mature patterning process, also exhibits an acceptable overall
cost. Moreover, the previous reports of the recovery of liquid metals from discarded electronics using
NaOH solution [35,36] indicate the potential for recycling liquid metals. By crushing discarded strain-sensing
gloves and soaking them in NaOH solution, the cost of the strain-sensing glove can be further reduced.

From sampled data of application demonstration, the good sensitivity of strain-sensing units can totally
meet the requirement of joint motion monitoring. However, many tiny strains with important information
about physical conditions in our bodies also need to be detected and visualized, such as pulses. If wearable
strain sensors for detecting pulses are fabricated using the strategy proposed in this study, a potential
approach introducing tiny structures into circuits could work well; that is, such rigid tiny structures may
result in necking of conductive paths when stretching, producing larger changes in resistance at the same
strain.

CONCLUSIONS
In summary, we have successfully developed a strain-sensing glove designed for finger gesture monitoring
and manipulating a machine hand. The glove has good responsiveness to strain and provides a high level of
wearing comfort. Sensing circuits of the strain-sensing glove are prepared by scraping liquid metal slurries
onto a disposable nitrile glove, offering good stretchability and durability during long-term use.
Subsequently, we used the strain-sensing glove to monitor different gestures, further verifying its feasibility
and sensitivity in practical sensing applications. Moreover, the strain-sensing glove can also be utilized to
manipulate a machine hand to perform symmetrical gestures, exhibiting its application potential as a soft
controller for human-machine interaction. The liquid metal-based circuits exhibit a good combination of
good strain response and low resistance value. Therefore, together with the comfortable wearability, such a
strain-sensing glove holds significant promise as a wearable flexible heater for active heat management in
cold environments. The manufacturing process of the strain-sensing glove is simple and low-cost, and the
whole process does not involve the use of environmentally toxic chemicals that require special operating
conditions. This aspect makes it highly suitable for commercial mass production and daily use.

DECLARATIONS
Authors’ contributions
Conceptualization, methodology, investigation, data acquisition and analysis, and the manuscript writing:
Wu P, Yiu CK
Conceptualization: Huang X, Yao K
Methodology: Li J, Xu G, Gao Y, Chow L, Jiao Y
Investigation: Zhao G, Yang Y
Conceiving research protocol, supervising the overall work, providing resources support, and reviewing and
editing the manuscript: Yu X

Availability of data and materials
Not applicable.