With the rapid development of smart wearable devices, flexible and biodegradable sensors are in urgent needs. In this study, ‘‘green" electrically conductive Ag nanowire (Ag NW)/cellulose nanofiber (CNF) hybrid...With the rapid development of smart wearable devices, flexible and biodegradable sensors are in urgent needs. In this study, ‘‘green" electrically conductive Ag nanowire (Ag NW)/cellulose nanofiber (CNF) hybrid nanopaper was fabricated to prepare flexible sensors using the facial solution blending and vacuum filtration technique. The amphiphilic property of cellulose is beneficial for the homogeneous dispersion of Ag NW to construct effective electrically conductive networks. Two different types of strain sensors were designed to study their applications in strain sensing. One was the tensile strain sensor where the hybrid nanopaper was sandwiched between two thermoplastic polyurethane (TPU) films through hot compression, and special micro-crack structure was constructed through the pre-strain process to enhance the sensitivity. Interestingly, typical pre-strain dependent strain sensing behavior was observed due to different crack densities constructed under different pre-strains. As a result, it exhibited an ultralow detection limit as low as 0.2%, good reproducibility under different strains and excellent stability and durability during 500 cycles (1% strain, 0.5 mm/min). The other was the bending strain sensor where the hybrid nanopaper was adhered onto TPU film, showing stable and recoverable linearly sensing behavior towards two different bending modes (tension and compression). Importantly, the bending sensor displayed great potential for human motion and physiological signal detection. Furthermore, the hybrid nanopaper also exhibited stable and reproducible negative temperature sensing behavior when it was served as a temperature sensor. This study provides a guideline for fabricating flexible and biodegradable sensors.展开更多
Advances in neural electrode technologies can have a significant impact on both fundamental and applied neuroscience. Here, we report the development of flexible and biocompatible neural electrode arrays based on a na...Advances in neural electrode technologies can have a significant impact on both fundamental and applied neuroscience. Here, we report the development of flexible and biocompatible neural electrode arrays based on a nanopaper substrate. Nanopaper has important advantages with respect to polymers such as hydrophilicity and water wettability, which result in significantly enhanced biocompatibility, as confirmed by both in vitro viability assays and in vivo histological analysis. In addition, nanopaper exhibits high flexibility and good shape stability. Hence, nanopaper-based neural electrode arrays can conform to the convoluted cortical surface of a rat brain and allow stable multisite recording of epileptiform activity in vivo. Our results show that nanopaper-based electrode arrays represent promising candidates for the flexible and biocompatible recording of the neural activity.展开更多
Cellulose nanopaper has shown great potential in diverse fields including optoelectronic devices,food packaging,biomedical application,and so forth,owing to their various advantages such as good flexibility,tunable li...Cellulose nanopaper has shown great potential in diverse fields including optoelectronic devices,food packaging,biomedical application,and so forth,owing to their various advantages such as good flexibility,tunable light transmittance,high thermal stability,low thermal expansion coefficient,and superior mechanical properties.Herein,recent progress on the fabrication and applications of cellulose nanopaper is summarized and discussed based on the analyses of the latest studies.We begin with a brief introduction of the three types of nanocellulose:cellulose nanocrystals,cellulose nanofibrils and bacterial cellulose,recapitulating their differences in preparation and properties.Then,the main preparation methods of cellulose nanopaper including filtration method and casting method as well as the newly developed technology are systematically elaborated and compared.Furthermore,the advanced applications of cellulose nanopaper including energy storage,electronic devices,water treatment,and high-performance packaging materials were highlighted.Finally,the prospects and ongoing challenges of cellulose nanopaper were summarized.展开更多
Environmental pollution is threatening human health and ecosystems as a result of modern agricultural techniques and industrial progress. A simple nanopaper-based platform coupled with luminescent bacteria Aliivibrio ...Environmental pollution is threatening human health and ecosystems as a result of modern agricultural techniques and industrial progress. A simple nanopaper-based platform coupled with luminescent bacteria Aliivibrio Jischeri （A. Jischeri） as a bio-indicator is presented here, for rapid and sensitive evaluation of contaminant toxicity. When exposed to toxicants, the luminescence inhibition of A. Jischeri-decorated bioluminescent nanopaper （BLN） can be quantified and analyzed to classify the toxicity level of a pollutant. The BLN composite was characterized in terms of morphology and functionality. Given the outstanding biocompatibility of nanocellulose for bacterial proliferation, BLN achieved high sensitivity with a low cost and simplified procedure compared to conventional instruments for laboratory use only. The broad applicability of BLN devices to environmental samples was studied in spiked real matrices （lake and sea water）, and their potential for direct and in situ toxicity screening was demonstrated. The BLN architecture not only survives but also maintains its function during freezing and recycling processes, endowing the BLN system with competitive advantages as a deliverable, ready-to-use device for large-scale manufacturing. The novel luminescent bacteria-immobilized, nanocelullose-based device shows outstanding abilities for toxicity bioassays of hazardous compounds, bringing new possibilities for cheap and efficient environmental monitoring of potential contamination.展开更多
Nanopaper has attracted considerable interest in the fields of films and paper research.However,the challenge of integrating the many advantages of nanopaper still remains.Herein,we developed a facile strategy to fabr...Nanopaper has attracted considerable interest in the fields of films and paper research.However,the challenge of integrating the many advantages of nanopaper still remains.Herein,we developed a facile strategy to fabricate multifunctional nanocomposite paper(NGCP)composed of wood-derived nanofibrillated cellulose(NFC)and graphene as building blocks.NFC suspension was consisted of long and entangled NFCs(10–30 nm in width)and their aggregates.Before NGCP formation,NFC was chemically modified with a silane coupling agent to ensure that it could interact strongly with graphene in NGCP.The resulting NGCP samples were flexible and could be bent repeatedly without any structural damage.Within the NGCP samples,the high aspect ratio of NFC made a major contribution to its high mechanical strength,whereas the sheet-like graphene endowed the NGCP with electrical resistance and electrochemical activity.The mechanical strength of the NGCP samples decreased as their graphene content increased.However,the electrical resistance and electrochemical activity of the NGCP samples both rose with increasing content of graphene.The NGCPs still kept advantageous mechanical properties even at high temperatures around 300℃ because of the high thermal stability of NFCs and their strong entangled web-like structures.In view of its sustainable building blocks and multifunctional characteristics,the NGCP developed in this work is promising as low-cost and high-performance nanopaper.展开更多
本工作通过低成本、简单、快速的真空过滤方法首次成功制备了一种独立的、无粘合剂的柔性聚吡咯:聚磺苯乙烯/纤维素纳米纸电极(PPy:PSS/CNP).多层结构的纤维素纳米纸具有较高的表面积和良好的机械强度,不仅提供了高的电活性区域,缩短了...本工作通过低成本、简单、快速的真空过滤方法首次成功制备了一种独立的、无粘合剂的柔性聚吡咯:聚磺苯乙烯/纤维素纳米纸电极(PPy:PSS/CNP).多层结构的纤维素纳米纸具有较高的表面积和良好的机械强度,不仅提供了高的电活性区域,缩短了电解质离子的扩散距离,而且还阻止了PPy在充电/放电过程中的体积膨胀/收缩.优化后的PPy:PSS/CNP在10 mV s-1时表现出3.8 F cm-2(对应于475 F cm-3和240 F g-1)的高比电容和良好的循环稳定性(在5000次循环后有80.9%的电容保持率).PPy:PSS/CNP在不同弯曲角度下的循环伏安曲线表明电极具有突出的柔韧性和电化学稳定性.此外,组装的对称超级电容器器件在功率密度为4.4 m W cm-2(550 m W c m-3)的情况下,提供了122μW h cm-2(15 W h cm-3)的高面积能量密度,这个值优于其他基于纤维素电极材料制备的器件.PPy:PSS/CNP电极结合了高电容性能、灵活性、易于制造和廉价多个优势,为开发下一代绿色、经济便携式和可穿戴电子产品提供了巨大潜力.展开更多
基金supported by the National Natural Science Foundation of China(51803191)the China Postdoctoral Science Foundation(2018M642782)the 111 project(D18023)
文摘With the rapid development of smart wearable devices, flexible and biodegradable sensors are in urgent needs. In this study, ‘‘green" electrically conductive Ag nanowire (Ag NW)/cellulose nanofiber (CNF) hybrid nanopaper was fabricated to prepare flexible sensors using the facial solution blending and vacuum filtration technique. The amphiphilic property of cellulose is beneficial for the homogeneous dispersion of Ag NW to construct effective electrically conductive networks. Two different types of strain sensors were designed to study their applications in strain sensing. One was the tensile strain sensor where the hybrid nanopaper was sandwiched between two thermoplastic polyurethane (TPU) films through hot compression, and special micro-crack structure was constructed through the pre-strain process to enhance the sensitivity. Interestingly, typical pre-strain dependent strain sensing behavior was observed due to different crack densities constructed under different pre-strains. As a result, it exhibited an ultralow detection limit as low as 0.2%, good reproducibility under different strains and excellent stability and durability during 500 cycles (1% strain, 0.5 mm/min). The other was the bending strain sensor where the hybrid nanopaper was adhered onto TPU film, showing stable and recoverable linearly sensing behavior towards two different bending modes (tension and compression). Importantly, the bending sensor displayed great potential for human motion and physiological signal detection. Furthermore, the hybrid nanopaper also exhibited stable and reproducible negative temperature sensing behavior when it was served as a temperature sensor. This study provides a guideline for fabricating flexible and biodegradable sensors.
基金We thank Prof. Qingfei Liu from School of Pharmaceutical Sciences in Tsinghua University for his kind help in cellulose homogenization. We thank Yuchen Lin for his help in AFM analysis. Y. F. thanks to the support from the National Natural Science Foundation of China （Nos. 21673057 and 31600868） and Beijing Science and Technology Program （No. Z161100002116010）. H. B. L. thanks to the support from BOE Technology Group Co., Ltd. under the project of nanopaper-based multifunctional flexible sensors and the National Key R＆D Program of China （No. 2017YFF0209901）.
文摘Advances in neural electrode technologies can have a significant impact on both fundamental and applied neuroscience. Here, we report the development of flexible and biocompatible neural electrode arrays based on a nanopaper substrate. Nanopaper has important advantages with respect to polymers such as hydrophilicity and water wettability, which result in significantly enhanced biocompatibility, as confirmed by both in vitro viability assays and in vivo histological analysis. In addition, nanopaper exhibits high flexibility and good shape stability. Hence, nanopaper-based neural electrode arrays can conform to the convoluted cortical surface of a rat brain and allow stable multisite recording of epileptiform activity in vivo. Our results show that nanopaper-based electrode arrays represent promising candidates for the flexible and biocompatible recording of the neural activity.
基金This work has been supported by the National Natural Science Foundation of China(32071720)and Key Technology Research and Development Program of Tianjin(19YFZCSN00950)+2 种基金from Tianjin Municipal Science and Technology Bureau,T.Xu thanks the China Postdoctoral Science Foundation(2021M702456)K.Liu acknowledges the financial support from the Tianjin Research Innovation Project for Postgraduate Students(2021YJSB198).W.Liu thanks the China Scholarship Council for the financial support(No.202108120056)and Innovation Project of Excellent Doctoral Dissertation of Tianjin University of Science and Technology(2020005)Open access funding provided by Shanghai Jiao Tong University
文摘Cellulose nanopaper has shown great potential in diverse fields including optoelectronic devices,food packaging,biomedical application,and so forth,owing to their various advantages such as good flexibility,tunable light transmittance,high thermal stability,low thermal expansion coefficient,and superior mechanical properties.Herein,recent progress on the fabrication and applications of cellulose nanopaper is summarized and discussed based on the analyses of the latest studies.We begin with a brief introduction of the three types of nanocellulose:cellulose nanocrystals,cellulose nanofibrils and bacterial cellulose,recapitulating their differences in preparation and properties.Then,the main preparation methods of cellulose nanopaper including filtration method and casting method as well as the newly developed technology are systematically elaborated and compared.Furthermore,the advanced applications of cellulose nanopaper including energy storage,electronic devices,water treatment,and high-performance packaging materials were highlighted.Finally,the prospects and ongoing challenges of cellulose nanopaper were summarized.
文摘Environmental pollution is threatening human health and ecosystems as a result of modern agricultural techniques and industrial progress. A simple nanopaper-based platform coupled with luminescent bacteria Aliivibrio Jischeri （A. Jischeri） as a bio-indicator is presented here, for rapid and sensitive evaluation of contaminant toxicity. When exposed to toxicants, the luminescence inhibition of A. Jischeri-decorated bioluminescent nanopaper （BLN） can be quantified and analyzed to classify the toxicity level of a pollutant. The BLN composite was characterized in terms of morphology and functionality. Given the outstanding biocompatibility of nanocellulose for bacterial proliferation, BLN achieved high sensitivity with a low cost and simplified procedure compared to conventional instruments for laboratory use only. The broad applicability of BLN devices to environmental samples was studied in spiked real matrices （lake and sea water）, and their potential for direct and in situ toxicity screening was demonstrated. The BLN architecture not only survives but also maintains its function during freezing and recycling processes, endowing the BLN system with competitive advantages as a deliverable, ready-to-use device for large-scale manufacturing. The novel luminescent bacteria-immobilized, nanocelullose-based device shows outstanding abilities for toxicity bioassays of hazardous compounds, bringing new possibilities for cheap and efficient environmental monitoring of potential contamination.
基金This research was funded by the National Natural Science Foundation of China(Grant No.31800487)the Natural Science Foundation of Heilongjiang Province of China(Grant No.QC2018018)+2 种基金the Fundamental Research Funds for the Central Universities(Grant No.2572019BB03)the Foundation of Key Laboratory of Pulp and Paper Science and Technology of Ministry of Education/Shandong Province of China(Grant No.KF201721)Any research results expressed in this paper are those of the writer(s)and do not necessarily reflect the views of the foundations.
文摘Nanopaper has attracted considerable interest in the fields of films and paper research.However,the challenge of integrating the many advantages of nanopaper still remains.Herein,we developed a facile strategy to fabricate multifunctional nanocomposite paper(NGCP)composed of wood-derived nanofibrillated cellulose(NFC)and graphene as building blocks.NFC suspension was consisted of long and entangled NFCs(10–30 nm in width)and their aggregates.Before NGCP formation,NFC was chemically modified with a silane coupling agent to ensure that it could interact strongly with graphene in NGCP.The resulting NGCP samples were flexible and could be bent repeatedly without any structural damage.Within the NGCP samples,the high aspect ratio of NFC made a major contribution to its high mechanical strength,whereas the sheet-like graphene endowed the NGCP with electrical resistance and electrochemical activity.The mechanical strength of the NGCP samples decreased as their graphene content increased.However,the electrical resistance and electrochemical activity of the NGCP samples both rose with increasing content of graphene.The NGCPs still kept advantageous mechanical properties even at high temperatures around 300℃ because of the high thermal stability of NFCs and their strong entangled web-like structures.In view of its sustainable building blocks and multifunctional characteristics,the NGCP developed in this work is promising as low-cost and high-performance nanopaper.
基金supported by the National Science Foundation(CMMI-2113948)Liang Y acknowledges the financial support from China Scholarship Council(201708510080).
文摘本工作通过低成本、简单、快速的真空过滤方法首次成功制备了一种独立的、无粘合剂的柔性聚吡咯:聚磺苯乙烯/纤维素纳米纸电极(PPy:PSS/CNP).多层结构的纤维素纳米纸具有较高的表面积和良好的机械强度,不仅提供了高的电活性区域,缩短了电解质离子的扩散距离,而且还阻止了PPy在充电/放电过程中的体积膨胀/收缩.优化后的PPy:PSS/CNP在10 mV s-1时表现出3.8 F cm-2(对应于475 F cm-3和240 F g-1)的高比电容和良好的循环稳定性(在5000次循环后有80.9%的电容保持率).PPy:PSS/CNP在不同弯曲角度下的循环伏安曲线表明电极具有突出的柔韧性和电化学稳定性.此外,组装的对称超级电容器器件在功率密度为4.4 m W cm-2(550 m W c m-3)的情况下,提供了122μW h cm-2(15 W h cm-3)的高面积能量密度,这个值优于其他基于纤维素电极材料制备的器件.PPy:PSS/CNP电极结合了高电容性能、灵活性、易于制造和廉价多个优势,为开发下一代绿色、经济便携式和可穿戴电子产品提供了巨大潜力.
