【作者】 王伟；

【导师】 李志健； 刘汉斌；

【作者基本信息】 陕西科技大学 ， 轻工技术与工程， 2022， 硕士

【摘要】 随着科学的进步与发展,电子垃圾成为困扰人们的一个难题。选择一种“绿色”的材料作为柔性电子基底显得十分重要。纸张由于具有柔性、轻量化、低成本、可降解、可再生、绿色环保等优点而受到关注,因此,以纸张作为柔性电子材料已经成为一个研究热点。本文以针叶木纤维以及石墨纳米片为原料,通过抄纸的方法制备出一种多功能的复合纸。通过纸张表面改性赋予其疏水性能,使其作为柔性传感材料可以在复杂的环境中使用;同时,也可以作为电热材料应用于柔性电热领域。主要研究内容和成果如下:(1)采用石墨纳米片与针叶木纤维抄造了复合纸,加入纤维素纳米纤维(CNF)来提高纸张的机械强度,并在复合纸表面上涂覆烷基烯酮二聚体(AKD)乳液赋予其超疏水性。得到的传感器既可用于应变检测,也可用于压力检测。传感器用来检测应变时,其应变系数(GF)可达18.99,响应时间可以达到0.3 s,通过1000次弯曲循环测试,证明其具有良好的工作稳定性,可以用来检测手指、手腕、肘部的弯曲等人体动作。更有趣地是,由于传感器的超疏水性,其被证明能够在高湿度环境以及水下检测手指的弯曲动作。用来检测压力时,在0-316.5 kPa范围内其灵敏度为0.019 kPa-1,在316.5-1421 kPa范围内其灵敏度为0.01 kPa-1,响应时间为0.3 s,其检测范围大于已报道的纸基柔性压力传感器。(2)通过抄纸法制备出石墨纳米片含量为22wt%的复合纸,表面喷涂聚二甲基硅氧烷(PDMS)之后再通过滴涂木质素纳米颗粒水分散液,高温固化后制备出超疏水的复合纸。得到的柔性应变传感器在空气中以及在水下的GF分别为10.9和14.6,响应时间分别为0.3 s和0.15 s,其不仅可以在空气中检测手指弯曲动作、不同频率的手腕弯曲、机器人运动过程中关节的弯曲,而且可以检测在水下手指的弯曲动作、玩具鱼摆尾的动作以及超声波,在水中可以经过10000次循环稳定性测试。得到的柔性压力传感器在空气中和在水下的灵敏度分别为0.02 kPa-1和0.38 kPa-1,响应时间分别为0.46 s和0.3 s,其不仅可以在空气中检测手指按压动作、不同大小压力、脚掌踩踏产生的压力,而且可以在水下检测手指按压动作、不同砝码的重量、以及玩具潜艇撞击产生的压力。(3)经过抄纸的过程将石墨纳米片和针叶木纤维结合,制备出纸基电热材料,通过热压工艺以及添加阳离子聚丙烯酰胺(CPAM)来提高纸张的电热性能。得到的纸基电热材料在6 V电压下,表面温度在1min的时间内可以达到122.2℃。经过100次重复加热循环证明其具有良好的循环稳定性。并且该纸基电热材料具有很好的柔性,可以在100分钟内不断弯曲的过程中,保持稳定的发热温度。最后,该纸基电热材料可以用于可穿戴电热设备、液体加热、飞机除冰。本文通过抄纸法制备出一种多功能的复合纸。这种多功能复合纸为解决电子垃圾富集问题提供了—种新的方案,为纸基传感器在水下的应用以及纸基材料在电热领域的应用提供了一种新的思路。更多还原

【Abstract】 With the development science and technology,e-waste has become a problem for people.It is very important to choose a "green" material as flexible electronic substrate.Paper has attracted much attention because of its advantages of flexibility,lightweight,low cost,biodegradability,renewable and environmental protection.Therefore,paper as a flexible electronic material has become a research hotspot.In this paper,a multifunctional composite paper was prepared from softwood fiber and graphite nanoplates.The surface modification of paper endows it with hydrophobic properties so that it can be used as flexible sensing material in complex environment.At the same time,it can also be used as an electrothermal material in flexible heating.The main research contents and achievements are as follows:(1)Graphite nanoplates and softwood fibers were used to gain composite paper.Cellulose nanofibers(CNF)were added to improve the mechanical strength.Alkylenone dimer(AKD)emulsion was coated on the surface of the composite paper to give it superhydrophobicity.The sensor can be used for strain and pressure detection.As a strain sensor,its gauge factor(GF)can reach 18.99 with a response time of 0.3s.The sensor has good stability through 1000 bending strain cycle,and can be used to monitor finger,wrist,elbow bending and other human motions.More interestingly,it can monitor finger bending in high humidity and under water due to the sensor’s superhydrophobicity.As a pressure sensor,its sensitivity(S)is 0.019 kPa-1 in the range of 0-316.5 kPa and 0.01 kPa-1 in the range of 316.5-1421 kPa,with a response time of 0.3 s.Its detection range is much wider than that of the reported flexible paper-based pressure sensor(2)The composite paper with graphite nanoplates content of 22 wt%was prepared by papermaking.After spraying polydimethylsiloxane(PDMS)on the surface,a superhydrophobic composite paper was prepared after curing at high temperature by dropping lignin nanoparticle aqueous dispersion.The GF of the flexible strain sensor are 10.9 and 14.6 with a response time of 0.3 s and 0.15 s in air and under water respectively.It can not only monitor finger bending,wrist bending at different frequencies,and joint bending during robot movement in air.In addition,it can monitor the movement of a finger,the movement of a toy fish wagging its tail,and the ultrasonic wave under water.It can go through 1,0000 bending cycles of stability under water.The sensitivity of the obtained flexible pressure sensor is 0.02 kPa-1 and 0.38 kPa-1 with a response time of 0.46 s and 0.3 s in air and under water respectively.It can not only detect the pressure generated by finger pressing action,different pressure and foot treading in air.It can also detect finger presses,weights of different weights,and pressure from the impact of the toy submarine under water.(3)Paper-based electrothermal materials are prepared by combining graphite nanoplates and softwood fibers in papermaking,whose electrothermal materials are improved by hot pressing process and adding cationic polyacrylamide(CPAM).Its surface temperature can reach 122.2℃ at 6 V voltage in lmin.It is proved that it has good stability after 100 times of repeated heating cycles.And it has outstanding flexibility which can maintain a stable heating temperature during bending cycles in 100 min.Finally,the paper-based electrothermal material can be used for wearable electrothermal devices,liquid heating,aircraft deicing.In this paper,a multifunctional composite paper was prepared by papermaking.It provides a new solution to the problem of e-waste enrichment and a new idea for the application of paper-based sensors in underwater and paperbased materials in electric heating.更多还原