# Underwater Highly Pressure-Sensitive Fabric Based on Electric-Induced Alignment of Graphene
## 4 Conclusions  
In summary, we have demonstrated a fabric pressure sensor with high sensitivity, good stability and good superhydrophobicity using the electric field synergistic plasma approach. The fabric sensor exhibits higher sensitivity (\(\Delta\)I/I\({}_{0}\) of 55) and fast response time (\(-\)100 ms) due to the additional structural deformation obtained by the three-dimensional alignment of graphene under electric fields. The sensor can be used for pressure, water level, and underwater motion detection because it exhibits excellent superhydrophobicity (WCA = 153.9\({}^{\circ}\)) and good repeatability due to the formation of alkyl long chains and the rough surface under plasma. Moreover, stable superhydrophobic surfaces maintained good electrical conductivity when immersed in acid-alkali solutions with ultrasonic treatment. The sensor can be integrated into electronic circuits to provide warnings for preset pressures, or the fabric sensor could be used in underwater wearable devices to detect the pressure environment in which the human body is subjected to being underwater in real-time. We believe that this highly sensitive superhydrophobic fabric sensor provides an efficient strategy for wearable sensors, especially in wet or underwater environments.  
The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/ma16041567/s1](https://www.mdpi.com/article/10.3390/ma16041567/s1)]([https://www.mdpi.com/article/10.3390/ma16041567/s1](https://www.mdpi.com/article/10.3390/ma16041567/s1)), Figure S1: DC electric field device diagram; Figure S2: The radio frequency capacitively coupled Ar plasma (RF-CCP); Figure S3: Effect of plasma discharge time on contact angle and roll angle of fabric; Figure S4: Pressure response curves of fabric flexible pressure sensors under different electric field induction directions; Figure S5: Cross-sectional morphology of composites under different electric field induction directions: (a) no electric field applied; (b) longitudinal electric field; (c) transverse electric field; Figure S6: Hysteresis test results;  
Figure 4: Resistive response and durability testing of sensors to different underwater behaviors. (**a**) Press the sensor in the water. (**b**) Tap the vessel wall with tweezers. (**c**) Blow on the water with an ear washing ball. (**d**) The resistance response curves of the small fish moving and stopping state; the inset is the simulated fish swimming mode to detect fish tail swing. (**e**) I\(-\)V response curves in different pH solutions. (**f**) I\(-\)V response curves of the sensor under different water temperature conditions.  
Figure S7: Vocal cord vibration monitoring; Table S1: Pharmaceutical chemistry measurement; Table S2 The sensing test system.  
**Author Contributions:** P.Z.: investigation, methodology, visualization, and writing--original draft. L.G.: methodology, visualization. W.L.: investigation, methodology. D.G.: conceptualization, writing--review, and editing. L.Y.: conceptualization, writing--review, and editing. Y.G.: conceptualization, funding acquisition, supervision, writing--review, and editing. J.S.: conceptualization, funding acquisition, supervision. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research was funded by the National Natural Science Foundation of China (No. 12175036, No. 11875104).  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Informed consent was obtained from all subjects involved in the study.  
**Data Availability Statement:** The data presented in this study are available within the article.  
**Conflicts of Interest:** The authors declare no conflict of interest.