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Zhu et al. Soft Sci 2024;4:17 https://dx.doi.org/10.20517/ss.2024.05 Page 29 of 38

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sensitivity (up to 22.3 kPa ) and pressure response range (0-22 kPa). Subsequently, the research team
mounted it on a robotic hand to realize intelligent mechanical applications such as braille recognition,
object grasping and roughness detection [Figure 14B (iii)].

PROSPECTS AND OUTLOOKS
In this review, we introduced the background and development of e-skins and outline the general strategies
of various types of e-skins for realizing different basic functions, along with the latest advances in
integrating these multiple functions into e-skin systems. We are pleased to see that the field of e-skins has
been showing rapid development and making great strides every year, and we consider that the following
trends will follow in the next period of time:

1. A major challenge remains how to integrate the various sensing characteristics better. This involves two
key points: (1) the preparation of multimodal e-skins that integrate diverse powerful sensing capabilities; (2)
the sensing characteristics are as non-interfering with each other as possible.

2. ML technologies will be applied in large numbers, accelerating the intelligent development of e-skins.

3. E-skins with special capabilities will increasingly emerge, expanding the applications of e-skins. For
example, e-skins with good biocompatibility and degradability [230-232] , suitable for medical and bioelectronic
applications; e-skins having high transparency [159,233] , suitable for photovoltaic and display applications. In
[200]
fact, there have been e-skins with special capabilities such as light-emitting [234-236] , thermal management ,
hydrophobicity [237,238] , UV resistance , electromagnetic radiation resistance [200,240] , and fire alarm .
[241]
[239]
4. Realizing these trends necessitates sophisticated designs in materials, circuits, processes, and signal
processing. This calls for deep interdisciplinary collaboration among scientists in various fields such as
chemistry, materials, mechatronics, electronics, information, and computers. For example, to achieve high
performance, new high-performance sensors need to be designed from the material design, device structure
design and other aspects, which requires the cooperation of scientists in the fields of chemistry, materials,
mechanics, and so on. The trend of cross-field cooperation is more obvious in developing complex e-skin
systems. The Multimodal E-skin Systems listed in the paper require fine design from chemistry, materials,
mechanics, electronics, etc. to combine high performance and high reliability, and the IoT-Integrated and
ML-Enabled E-skin Systems listed in the article involve a large number of technologies in the fields of
electronics, information science, and computers. The applications of e-skins also require the contributions
of multiple disciplines, such as medicine, biology, materials, chemistry, mechanics, electronics, and
information technology, to be realized. And for the application of e-skin in other lesser-known fields, it is
even more important to have cross-disciplinary collaboration to help inspire, promote, and apply. It is clear
that these high-level, cutting-edge visions cannot be easily realized by traditional chemical and materials
scientists alone and that cross-disciplinary research is the order of the day.

5. The signal communication in e-skin systems needs to be reformed. For example, for the synchronized
remote control, which can be foreseen that such scenarios will inevitably become increasingly prevalent in
the future, low latency is necessary, which means the requirements for fine material and structural design to
improve the response speed, interface impedance, and other characteristics of the new e-skins [242,243] .

6. Brain-computer interface (BCI) technology has made breakthroughs one after another in recent
years [244,245] . In fact, it is a further in-depth development of the HMI concept, and it is foreseeable that e-skin
will gain a lot of applications in this field. Similar to healthcare applications, but furthermore, the