Development And Performance Study Of Smart Pressure Socks

With the progress of textile materials,electronic technology,biotechnology and communication technology,smart textiles have attracted more and more scholars’ attention and research.Smart textiles integrate various technologies such as textile and garment,electronic information,bio-sensing,physical sensing and so on.It not only meets the basic needs of consumers for wearing warm clothes,but also gives textile and garment sensing and response processing functions.It can monitor human physiological data and movement data.The Smart textiles should be maintained soft and comfortable to ensure the wearability of smart textiles in the wearing process,when realizing the functions of data acquisition.And the research of flexible sensors is one of the key tasks in the development of smart textiles.Knitted products are soft,easily deformed and have large contact area with human body,so they become excellent carriers of flexible sensors.At present,the strain sensors for fabric structure are basically based on knitting structure at home and abroad.Silver-plated conductive yarn is the main knitting material for flexible sensors.Most of the inlaid flexible sensor smart textiles are in the form of seamless underwear,while the research on intelligent textiles for leg products is less.This subject takes pressure socks as the main body,studies the structure and performance of silver-plated conductive yarn,chooses appropriate materials for knitting;chooses appropriate knitting technology and structure,knits flexible sensors at the corresponding pressure gradient points;verifies the feasibility of flexible sensors for leg-lifting motion monitoring;study how the structure and size of the flexible sensor influence its resistance,and analysis the resistance stability after stretching,friction and washing.Specific research contents are as follows:(1)Select and analyze the materials of pressure socks,and test their mechanical properties.Test the basic properties conductivity,simulate dyeing process and oxidation environment,study the effects of dyeing and oxidation on the conductive yarns’ resistance and select the suitable conductive yarns for knitting.(2)Choose appropriate hosiery machine to knit smart pressure socks,design the knitting process parameters according to the characteristics of each part,design the organizational structure of flexible sensor,and test the basic performance of intelligent pressure socks,including its density,thickness,permeability,elastic recovery performance and pressure gradient.(3)The volunteers wear intelligent pressure socks with embedded flexible sensors.While the volunteers lift their legs,the resistance changes of flexible sensors are monitored at the same time,and function of human motion monitoring is verified.(4)Test the conductivity,stress sensing and stability of flexible sensors,including sensitivity and repeatability,and stability including washing resistance and friction resistance.Through a series of experiments,the following conclusions are drawn.Nylon-coated polyurethane yarn has excellent wear resistance and fabric resilience.Through mechanical properties testing,the elongation of 280/40/40 polyamide polyurethane yarn reaches 378.21%,and 40/40/40 polyamide polyurethane yarn reaches 257.72%,which meets the requirments of the pressure socks yarns.Silver-plated conductive yarn meets the requirements of knitting yarn,after comprehensive testing and analysis of conductive yarn’s conductivity,dyeing stability and tensile stability,77.78 dtex antioxidant silver-plated conductive yarn is finally selected as the main knitting material of flexible sensor.Choose Marz CC4-II single hosiery machine to knit the sample.Design two weaves including one separate one and one separate three,nine different sizes,totally 18 socks.The resistance variation period of the flexible sensor is basically the same as that of the volunteer’s leg lifting action period,which verifies the possibility of the flexible sensor to monitor the movement.The resistance fluctuation between valleys ranges from 0.07Ω~ 0.94Ω.The Conductivity test and stress sensing performance test show that the smaller the fabric density,the resistance of the flexible sensor is better.At the same position(same density),the resistance of one separate one weave is larger than that one separate three weave.Sensitivity is opposite.With the same number of horizontal columns,the more the number of longitudinals,the resistance and sensitivity are greater.With the same number of longitudinals,the more horizontal columns,the resistance and the resistance sensitivity are smaller.All the flexible sensors have excellent repeatability;the friction resistance of the one separate one weave is greater than one separate three weave.The less number of horizontal columns,friction resistance of the flexible sensor is better,and the more the number of longitudinals,the friction resistance of the flexible sensor is better.Through orthogonal experiments,it is concluded that the one separate one weave flexible sensor with 18 horizontal columns,20 longitudinals and Bpart has the best washing stability.In this paper,silver-plated conductive yarn is used as the main material of flexible sensor.It explored the sensing performance and resistance stability of flexible sensor.Its action monitoring function is verified.It also studied the influence of different structure,size and density on the performance of flexible sensor.It provides a theoretical basis for the structural design and weave selection of the flexible sensors.