Flexible carbonized cotton/thermoplastic polyurethane composites with outstanding electric heating and pressure sensing performance

2022 ◽  
pp. 004051752110698
Author(s):  
Haisu Ni ◽  
Shu Fang ◽  
Tanyu Wang ◽  
Yitao Liu ◽  
Hao Liu ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Flexible Electronics ◽  
Heating Temperature ◽  
Thermoplastic Polyurethane ◽  
Electric Heating ◽  
Cotton Fabrics ◽  
Superior Performance ◽  
Pressure Sensing ◽  
Polyurethane Composites ◽  
Sensing Performance

Although flexible wearable conductive textiles for various applications have attracted great attention from researchers in recent years, it is still a great challenge to fabricate conductive textiles with the advantages of a simple fabrication process, excellent flexibility, environmental friendliness, and superior performance. Carbonized cellulose materials are gradually emerging in flexible electronics due to their flexibility, low cost, abundant raw materials, and electrical conductivity. Herein, carbonized cotton fabrics were fabricated from cotton fabrics via a simple carbonization process. Then carbonized cotton/thermoplastic polyurethane composites, with excellent electric heating performance and pressure sensing performance, were fabricated through a dip-and-dry method. Carbonized cotton/thermoplastic polyurethane composites show satisfactory electrical conductivity, electric heating temperature rising performance, heating stability, and resistance stability. The surface temperature of carbonized cotton/thermoplastic polyurethane composites can reach ≈53°C within 1.5 min at 5 V. Besides this, the fabricated flexible pressure sensor based on carbonized cotton/thermoplastic polyurethane composites exhibits the combined superiority of a wide working range (0–16 kPa), high sensitivity (98.77 kPa−1), and excellent durability (>4000 cycles). Moreover, the finger motions and wrist pulse can be monitored in real time. These results demonstrate the potential application value and broad developmental prospects of carbonized cotton/thermoplastic polyurethane composites in flexible wearable electronics.

scholarly journals Sizes dependence of electrothermal temperature of carbon nanotube films and evaluation method of electrical conductivity by thermal parameter

2021 ◽  
Author(s):  
Shaojun Wu ◽  
Suna Cha ◽  
Hongliang Hou ◽  
Xiang Xue
Keyword(s):  
Electrical Conductivity ◽  
Steady State ◽  
Carbon Nanotube ◽  
Heating Temperature ◽  
Electric Heating ◽  
Electrical Heating ◽  
Maximum Temperature ◽  
Electric Heater ◽  
Carbon Nanotube Film ◽  
Nanotube Films

Carbon nanotube films have a great potential for the application of flexible electrothermal film, most attention has been only devoted into aspects of three different electrical heating sections, including the temperature growth section, the steady-state maximum temperature section and the temperature decay section, of electric heating carbon nanotube films in terms of electrothermal characteristics, a systematical study concerning the sizes dependence of electrothermal characteristics is inadequate. Herein, quantitative expressions concerning electric heating temperature and geometrical dimension of carbon nanotube film were proposed, and according to the relationships, the steady-state temperature could be determined by the length, width, thickness or area of carbon nanotube film, as well as other electrical and thermal parameters. The results demonstrated that smaller area, length-to-width ratio and thickness are conducive to reach a higher electric heating temperature of films at same applied electrical power while hysteresis of response time and cooling time would not be introduced, comparing to other types of carbon nanotube films. These characteristics and the obtained quantitative relations could contribute to design of carbon nanotube films as electric heater efficiently. On the other hand, a method to estimate electrical conductivity of conductive film materials was proposed on the basis of the aforementioned relationships, which put forward a way of thinking from the thermal point of view.

scholarly journals Ag/VO2/Ag sandwich nylon film for smart thermal management and thermo-responsive electrical conductivity

2021 ◽  
pp. 152808372098654
Author(s):  
Linghui Peng ◽  
Lingling Shen ◽  
Weiren Fan ◽  
Zichuan Liu ◽  
Hongbo Qiu ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Thermal Comfort ◽  
Thermal Management ◽  
Flexible Electronics ◽  
Sandwich Structure ◽  
Outdoor Thermal Comfort ◽  
Ir Radiation ◽  
Indoor Space ◽  
Layer Structures ◽  
Radiation Management

Due to the effects of climate changing, the importance of outdoor thermal comfort has been recognized, and has gained more and more research attentions. Unlike indoor space where air conditioning can be easily implemented, outdoor thermal comfort can only be achieved by localized thermal management. Using textile is a simple but energy-saving way to realize outdoor thermal comfort. Herein, we report the design of a smart thermal management film with the silver/vanadium dioxide/silver (Ag/VO2/Ag) sandwich structure prepared by one-dimensional (1 D) nanowires. It was found that the Ag/VO2/Ag sandwich film was able to lower the temperature by around 10 °C under intense infrared (IR) radiation. In addition, the Ag/VO2/Ag sandwich structure film showed a thermo-responsive electrical conductivity and an outstanding bending stability, due to network structure formed by nanowires. It was experimentally proved that this sandwich structure was superior to other layer structures in IR shielding performance and thermo-responsive electrical conductivity. The as-prepared Ag/VO2/Ag sandwich structure film has great potential for various applications such as wearable devices, flexible electronics, medical monitors and smart IR radiation management.

scholarly journals Electrically Conductive Networks from Hybrids of Carbon Nanotubes and Graphene Created by Laser Radiation

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1875
Author(s):  
Alexander Yu. Gerasimenko ◽  
Artem V. Kuksin ◽  
Yury P. Shaman ◽  
Evgeny P. Kitsyuk ◽  
Yulia O. Fedorova ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Laser Irradiation ◽  
Flexible Electronics ◽  
Threshold Energy ◽  
Wavelength Region ◽  
Hybrid Nanostructures ◽  
Graphene Sheets ◽  
Electrically Conductive ◽  
Walled Carbon Nanotubes

A technology for the formation of electrically conductive nanostructures from single-walled carbon nanotubes (SWCNT), multi-walled carbon nanotubes (MWCNT), and their hybrids with reduced graphene oxide (rGO) on Si substrate has been developed. Under the action of single pulses of laser irradiation, nanowelding of SWCNT and MWCNT nanotubes with graphene sheets was obtained. Dependences of electromagnetic wave absorption by films of short and long nanotubes with subnanometer and nanometer diameters on wavelength are calculated. It was determined from dependences that absorption maxima of various types of nanotubes are in the wavelength region of about 266 nm. It was found that contact between nanotube and graphene was formed in time up to 400 fs. Formation of networks of SWCNT/MWCNT and their hybrids with rGO at threshold energy densities of 0.3/0.5 J/cm2 is shown. With an increase in energy density above the threshold value, formation of amorphous carbon nanoinclusions on the surface of nanotubes was demonstrated. For all films, except the MWCNT film, an increase in defectiveness after laser irradiation was obtained, which is associated with appearance of C–C bonds with neighboring nanotubes or graphene sheets. CNTs played the role of bridges connecting graphene sheets. Laser-synthesized hybrid nanostructures demonstrated the highest hardness compared to pure nanotubes. Maximum hardness (52.7 GPa) was obtained for MWCNT/rGO topology. Regularity of an increase in electrical conductivity of nanostructures after laser irradiation has been established for films made of all nanomaterials. Hybrid structures of nanotubes and graphene sheets have the highest electrical conductivity compared to networks of pure nanotubes. Maximum electrical conductivity was obtained for MWCNT/rGO hybrid structure (~22.6 kS/m). Networks of nanotubes and CNT/rGO hybrids can be used to form strong electrically conductive interconnections in nanoelectronics, as well as to create components for flexible electronics and bioelectronics, including intelligent wearable devices (IWDs).

Formation of Tricalcium Silicate Prepared by Electric and Microwave Sintering

2010 ◽  
Vol 148-149 ◽  
pp. 1119-1123
Author(s):  
Kai Ke ◽  
Bao Guo Ma ◽  
Xiao Liang Wang ◽  
Xiang Guo Li
Keyword(s):  
Heating Temperature ◽  
Microwave Sintering ◽  
Electric Heating ◽  
Tricalcium Silicate ◽  
Experimental Results ◽  
X Ray Diffraction ◽  
X Ray ◽  
Conventional Sintering ◽  
Sintering Method

A microwave sintering method was used to prepare C3S from Ca(OH)2, SiO2 and MexOy. f-CaO assay, X-ray diffraction and SEM were used to characterize the sintered samples.The results indicated that ion oxides played a very important role in C3S formation in conventional sintering, the use of MexOy as an additive was so effective in promoting C3S formation. The experimental results showed that samples were heated at an electric heating temperature(1500°C) and then further sintered with microwave for 30~60 min, tricalcium silicate could be formed with kilogram step. The new burning technique can greatly increase the forming speed of tricalcium silicate, MnO2, CuO and Ni2O3 could enhance the microwave sintering.

Electrical conductivity enhancement in thermoplastic polyurethane-graphene nanoplatelet composites by stretch-release cycles

2017 ◽  
Vol 110 (12) ◽  
pp. 121904 ◽  
Author(s):  
Pietro Cataldi ◽  
Luca Ceseracciu ◽  
Sergio Marras ◽  
Athanassia Athanassiou ◽  
Ilker S. Bayer
Keyword(s):  
Electrical Conductivity ◽  
Thermoplastic Polyurethane ◽  
Graphene Nanoplatelet ◽  
Conductivity Enhancement

Screen Printing Fine Pitch Stretchable Silver Inks onto a Flexible Substrate for Wearable Applications

2018 ◽  
Vol 2018 (1) ◽  
pp. 000665-000671
Author(s):  
Jianbiao Pan ◽  
Malcolm Keif ◽  
Joshua Ledgerwood ◽  
Xiaoying Rong ◽  
Xuan Wang
Keyword(s):  
Sheet Resistance ◽  
Flexible Electronics ◽  
Screen Printing ◽  
Flexible Substrate ◽  
Thermoplastic Polyurethane ◽  
Organic Substrate ◽  
Printing Process ◽  
Silver Ink ◽  
Fine Pitch

Abstract The lightweight and bendable features of printed flexible electronics are increasingly attractive. Currently stretchable silver inks are formulated for wide traces, typically larger than 2 mm. To attach ultra-thin silicon chips that have fine pitch onto printed organic substrate, it is necessary to print fine trace width/space that matches the pitch of the chips, which may be less than 200 microns. This paper presents the development and optimization of the screen printing process for printing stretchable silver ink onto stretchable thermoplastic polyurethane (TPU) substrate. A test vehicle was designed including 50 μm/5 mm (line width/line length) to 350 μm/35 mm lines (at 4 biases). The stretchable ink selected was DuPont PE 873 and Dupont's PE 5025 ink (non-stretchable conductive flake silver) was used as a “control” to baseline the printing process. The substrate used was Bemis TPU ST604. The experiment was done on a DEK Horizon 03i printer. A DEK squeegee 200 (Blue) and a DEK 265 flood bar (200 mm) were used. A 2-level factorial design with three replicates was selected to investigate the effect of process parameters on the quality of prints. The quality of the prints is characterized by 1) resistance of traces, 2) sheet resistance, 3) z-axis height, and 4) trace width/spacing. We observed significant noise in the z-axis printed silver ink height measured by profilometry and concluded z-axis height is not a good response variable for characterizing screen printing stretchable silver ink onto TPU substrate, mainly due to high roughness of the TPU substrate. We proposed calculated sheet resistance based on the measured resistance value, trace width, and trace length, which can replace trace height measurements on rough profile substrates. We found that squeegee pressure and emulsion thickness have statistically significant effects on calculated sheet resistance of print traces while print speed does not have statistically significant effects. In our experiment setting levels, the lower the squeegee pressure, the lower the calculated sheet resistance that is achieved. The emulsion with higher emulsion over mesh (EOM) is better than the emulsion with lower EOM since it can achieve lower sheet resistance. After optimizing the screen printing process, we were able to print 100 μm (4 mils) trace width and spacing with high consistency.

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