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Wang et al. Soft Sci. 2025, 5, 28 https://dx.doi.org/10.20517/ss.2025.11 Page 9 of 29

micro-pyramid-structured silicon substrates via plasma-enhanced chemical vapor deposition (PECVD) and
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used as piezoresistive electrodes, achieving 64 units/cm spatial resolution. The sensor array, integrated into
a robotic fingertip, successfully replicated 3D pulse wave shapes for diagnostic visualization, highlighting
the high-density array’s potential in remote health monitoring. Mei et al. fabricated a PDMS-based sensor
film using self-assembled and patterned spiky carbon nanospheres as strain-sensing units, achieving a high
[29]
array density of 100 units/cm with good consistency . This array can conformally cover various surfaces,
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detect strain gradients, track deformations, and monitor strains in real-time for accurate distribution
mapping [Figure 5].
Zhao et al. developed a PRSA based on sandpaper-like spiky microstructures . The array, with a density of
[93]
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1,134.63 cm and 4,096 sensing units, combined with machine learning, achieved 98.47% accuracy in
recognizing 12 mahjong tile faces. Its high density and consistency enable high-resolution spatial sensors,
allowing detailed pressure distribution mapping of complex 3D patterns. As shown in the fabrication
process [Figure 6A], PDMS films with MWCNTs and flexible array electrodes are integrated. Experiments
confirmed the relationship between sandpaper mesh count and array uniformity, with 1500-mesh
sandpaper used as the pressure-sensitive layer to create an array of 4,096 sensing units. Tang et al.
constructed a high-density tactile sensor array by monolithically integrating lanthanum-doped indium zinc
oxide thin-film transistor (Ln-IZO TFT) arrays with CNTs/PDMS resistive pressure-responsive layers
featuring micro-pyramid/nanopillar structures . Ln-IZO TFT arrays were prepared on polyimide (PI)
[30]
films, and then pressure-sensing films with 3D CNTs/PDMS hierarchical micro/nanostructures were
fabricated. Finally, the Ln-IZO TFT arrays and pressure-sensing films were integrated, with each pixel
containing one Ln-IZO TFT and one pressure sensor, enabling fine-texture differentiation and high-
resolution pressure-distribution imaging. This work provided an effective solution to endow robotics with a
human-like sense of touch.

With the increasing density, integration and multifunctionality of sensor devices, heat buildup can lead to
signal drift, mechanical fatigue and even device failure, especially in wearable devices and high-density
sensor networks . Thermal management plays a crucial role in the performance and reliability of flexible
[94]
sensor devices. Effective heat dissipation is essential not only to maintain long-term operational stability
and sensing accuracy, but also to ensure user safety in wearable applications. To address these challenges,
current strategies commonly involve passive and active thermal management. Kang et al. presented a
nanocomposite of aligned boron nitride (BN) nanosheet islands with porous PDMS foam to have
mechanical stability and non-thermal interference . The heat pathways are then formed only in the
[95]
structured BN islands of the composite. The porous PDMS foam can be applied as a thermal barrier
between structured BN islands to inhibit thermal interference in multiple device arrays. The selective heat-
dissipating composites with thermal barriers can work as a promising heat sink and heat guidance in
multiple chip array electronics and wearable electronic systems. Peng et al. proposed an integrated cooling
(i-Cool) textile with unique functional structure design for personal perspiration management . By
[96]
integrating heat-conductive pathways and water transport channels effectively, i-Cool exhibits enhanced
sweat evaporative cooling efficiency - not merely a liquid sweat-wicking function. The practical feasibility of
the textile design principles was demonstrated, exhibiting decent performance. This work opens a new door
and provides new insights for flexible sensors in thermal management. Both of the above works involved in
wearable electronics pertain to passive thermal management, which mainly relies on material properties and
special structural designs to achieve heat dissipation. In contrast, active strategies cool or heat by actively
transferring heat from or to the human body with external input. Lee et al. proposed an adaptive robotic
skin with a microfluidic cooling device. The adaptive robotic skin consists of an array of uniform gallium-
microgranule-based tunable pressure sensors (GM-TPSs), with top and bottom flexible electrode layers and