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材料：[https://zh.wikipedia.org/wiki/聚偏二氟乙烯]

在极化后具有铁电性，6-7pC/N

摘要：
先介绍了一下线性响应的好处：
Flexible pressure sensors with a high sensitivity over a broad linear range can simplify wearable sensing systems without additional signal processing for the linear output, enabling device miniaturization and low power consumption

结构：multilayer interlocked microdome geometry

多层连锁微圆顶几何结构

1. 对于静态压力和动态压力有极高的分辨率 47.7 kPa−1, 1.3 Pa minimum detection
2. 极宽的线性响应范围(0.0013−353 kPa)，且响应时间极快20ms
3. 高可靠性 在272kPa下重复5000个周期

实验章节

GO: 按照修改的Hummers方法：[48,49]

1. 石墨烯粉末， $K_2{S}_2{O}_8$， $P_2{O}_5$ 分散到浓硫酸溶液中concentrated $H_{2}S{O}_4$ solution。 在80摄氏度下搅拌4.5h
2. 之后用去离子水稀释，之后过滤，使用去离子水清洗，直到PH=7
3. 得到的滤液在真空30摄氏度下干燥一晚上
4. 预先氧化的石墨烯分散到浓硫酸中，之后在剧烈搅拌的条件下缓慢加入$KMn{O}_4$,之后再36摄氏度的条件下搅拌2h
5. 之后使用去离子水稀释，在36摄氏度下搅拌2h
6. 接下来将30%的$H_2{O}_2$添加到混合物中，颜色会变为亮黄色，并伴有强烈的气泡
7. 混合物搅拌1h，在10%的HCL中离心几次除去残留的盐块，之后透析来调节酸度
8. 最后溶液在30度的真空下干燥凝聚。分散到DMF溶剂中，超声处理获得GO-DMF溶液
9. 在混合石墨烯和PVDF之前，PVDF首先分散到DMF溶剂中，PVDF-DMF溶液(20 wt%)与GO-DMF(10mg/ml)混合。
10. GO/PVDF浇注到玻璃基底和微圆顶模具中。浇注的溶液首先在加热板上50摄氏度干燥2h，之后早在160度的真空干燥炉中退火2h，将GO还原到rGO，去掉残留的DMF

制造3 × 3和4 × 8阵列，PET支撑层使用溅射系统溅射铂电极，multilayer interlocked microdome rGO/PVDF composite films被夹在电极中间。

看完这个过程迷得很。。。。。

introduction

另一个要求是能区分触觉刺激：

Another significant requirement for e-skins with human skin-like tactile sensing properties is the discrimination of spatiotemporal tactile stimuli, including static and dynamic pressure, which allows dexterous manipulation of objects and the perception of vibration and surface textures[6,7]

集成到各种应用中的要求：大的动态响应范围和高灵敏度且具有线性响应特性
In addition, to use e-skins for various
applications as a single device, they should have a large dynamic sensing range and linear pressure-sensing capability to constantly maintain their high sensitivity, even in a high-pressure region[8,9]

举例说明能干啥

E-skins with a high sensitivity over a broad sensing range can perceive, for example, subtle pressure of a light breeze and respiration (<1 kPa), medium pressure of pulse pressure and gentle touch (1−10 kPa), and large pressure of plantar foot pressure (>10 kPa)

有研究只在提升前述要求的某一些，但是全部实现任然很有挑战性：

Although several approaches have been adopted to improve some of the aforementioned requirements of e-skins, the combination of all of these properties in a single eskin remains a challenge[9-11]

另起一段：
介绍人体皮肤的原理 ：
As an ideal sensory system, human skin can perceive and differentiate various tactile sensations under different mechanical stimuli.[12] In particular, various sensory receptors are embedded in the human skin, which transduce information from applied stimuli, such as magnitude, distribution, and frequency, into tactile sensation[13]

介绍皮肤结构：表皮和真皮之间的中间脊结构能高效的传输信号,并解释了一下原因

In addition, the special intermediate ridge structure between the dermal and epidermal layers efficiently transmits tactile signals from the skin surface to sensory receptors located in interlocked ridge structures due to the effective stress concentration between the dermal and epidermal layers with different moduli[14-16]

Pan 基于空心球微结构的压力传感器[3]
Pan et al.3 demonstrated hollow sphere microstructure- based pressure sensors with a high sensitivity of 133 kPa−1,

To differentiate spatiotemporal tactile stimuli, interlocked microdome-based e-skins have been suggested【7】

缺点：
压力不能大于50kPa，没有实现线性响应
This work showed highly sensitive and multifunctional tactile sensing performance with various transduction modes, but the dynamic pressure-sensing range was still under 50 kPa and a linear sensing capability could not be achieved

Therefore, a significant challenge remains in the development of e-skins with new device designs to realize a large dynamic pressure range and linear tactile sensing performances

另起一段：介绍本论文的工作

第一句：实现功能 based on 结构

In this paper, we demonstrate a flexible ferroelectric sensor with ultrahigh pressure sensitivity and linear response over an exceptionally broad pressure range based on the ferroelectric composites with a multilayer interlocked microdome geometry

第二句： 由于PVDF和rGO(还原石墨烯)的导电性和铁电性,能够感知静态和动态压力，基于压阻和压电效应。

Due to the conductive and ferroelectric nature of polymer composites comprising poly(vinylidene fluoride) (PVDF) and reduced graphene oxide (rGO), our e-skins can perceive and differentiate static and dynamic pressures using piezoresistive and piezoelectric modes。

第三句： 接下来介绍结构组成：
单层受中间脊启发，构建三层结构
Each layer of e-skins comprises interlocked microdome arrays inspired by interlocked ridge structures between the dermal and epidermal layers, and three interlocked layers are stacked for the fabrication of multilayer eskins.

第四句：解释线性响应的原因【Figure 1a】
与单层结构相比，增加的接触面积和层之间高效的压力分布
While previous pressure sensors exhibit nonlinear or narrow range linear sensing, our e-skins can maintain their high- sensitivity and linear response over a broad pressure range due to the increased contact area change and efficient stress distribution between stacked layers compared with single-layered e-skins

第七句：
具体介绍三种压力范围（低，中，高）下的应用展示
For example, our e-skins were used for precise detection of weak gas flow and acoustic sound in a low-pressure regime and for monitoring respiration and pulse pressure in a medium-pressure regime. In addition, the large dynamic range pressure-sensing capability of e-skins was employed for plantar pressure monitoring in a high-pressure regime

结果和讨论

这都不重要，得看48和49那两篇论文。

Figure 1d 横截面的SEM图像
Figure 1d shows the cross-sectional scanning electron microscopy (SEM) image of an rGO/PVDF composite film with interlocked microdome multilayer
structures.