In the context of the rapid development of artificial intelligence and robotics,their application scenarios are continuously expanding to a variety of complex environments,with increasing attention being paid to the u...In the context of the rapid development of artificial intelligence and robotics,their application scenarios are continuously expanding to a variety of complex environments,with increasing attention being paid to the use of flexible sensors in lowtemperature environments.In this study,an ionic hydrogel was synthesized using acrylamide(AM),hydroxyethyl cellulose(HEC),and lithium chloride(LiCl)as composites.This hydrogel exhibits high adhesion,excellent sensitivity(gauge factor(GF)=2.84),rapid response time(100 ms),exceptional stretch ability(>1776%),high toughness(2.5 MJ/m^(3)),and the ability to maintain detectability at low temperatures(-60℃).HEC imparts reliable mechanical properties to the sensor through hydrogen bonding interactions of its hydroxyl groups.LiCl ensures that the sensor has outstanding antifreezing properties,maintains good conductivity and mechanical performance.Used for robotic attitude detection,the sensor demonstrated accurate recognition of various joint movements at both 20 and -20℃.This technology was extended to industrial operations and maintenance,where a mechanical claw was used to grasp parts at both room temperature and low temperature.A convolutional neural network deep learning algorithm was employed to identify and classify eight types of parts,achieving an impressive recognition accuracy of 98.8%.The polyacrylamide(PAM)/HEC/LiCl hydrogel sensor demonstrates the capability for wide-temperature range detection in flexible robotics,holding significant potential for future applications in human-machine interaction,tactile perception,and related fields.展开更多
It is a challenge to determine the dominant topological characteristics of mechanical properties of adhesive interfaces.In this paper,we used graph theory and molecular dynamics simulation to investigate the influence...It is a challenge to determine the dominant topological characteristics of mechanical properties of adhesive interfaces.In this paper,we used graph theory and molecular dynamics simulation to investigate the influence of topological characteristics on the strength and toughness of highly cross-linked polymer interface systems.Based on the microstructure of the adhesive system,we extracted the dominant topological characteristics,including the connectivity degree(D)that determines the yield strength,and the average node-path(P)and the simple cycles proportions(R)that determine the deformability and load-bearing capacity during the void propagation respectively,which co-determine the toughness.The influence of the wall-effect on the dominant topological characteristics was also analyzed.The results showed that the interfacial yield strength increases with the increase of D,while the toughness increases with the increase of P and R.The wall-effect has a significant influence on D,P,and R.The strong wall-effect causes the enrichment of amino groups near the wall and insufficient cross-linking away from the wall,leading to the lower D and R,i.e.,the lower yield strength and load-bearing capacity during the void propagation.With the attenuation of the wall-effect,the D increases gradually,while the P and the R first increase and then decrease,showing an optimized wall-effect for the toughness of the adhesive interface.This paper reveals the dominant topological characteristics of adhesive interfacial strength and toughness,providing a new way to modulate the mechanical properties of polymer adhesive interface systems.展开更多
It is of great significance to design epoxy coatings with superior antibacterial properties and high adhesive properties, as well as excellent processing, superior durability, and high transparency. However, it is sti...It is of great significance to design epoxy coatings with superior antibacterial properties and high adhesive properties, as well as excellent processing, superior durability, and high transparency. However, it is still a challenge because of the common complex design and synthesis. Herein, the bio-based monomer protocatechuic acid(PCA) was used as raw material, the catechol structure with high bonding and antibacterial properties was introduced into the flexible alkane segment of ethylene glycol diglycidyl ether(EGDE) through an efficient, and green method, and it was cured with isophorone diamine(IPDA) to prepare corresponding thermosets. The cured resins exhibited excellent allaround qualities, particularly in bonding and antibacterial. When 30% PCA was added to pure epoxy resin, the adhesion between substrate and coating increased from 4.40 MPa to 13.60 MPa and the antibacterial rate of coating against E. coli and S. aureus could approach 100%. All of this is due to the fact that the catechol structure present in PCA has the ability to interact with various substrates and alter the permeability of bacterial cell membranes. The architecture of this method offers a fresh approach to dealing with the issues of challenging raw material selection and complex synthesis techniques.展开更多
The surface of a peach is known to exhibit spe- cial wettability and adhesion behaviors. We disclose that the peach surface is covered with long and short indumentums. The long indumentums are covered mainly with hydr...The surface of a peach is known to exhibit spe- cial wettability and adhesion behaviors. We disclose that the peach surface is covered with long and short indumentums. The long indumentums are covered mainly with hydrophobic wax molecules, while the short indumentums are coated mostly with hydrophilic polysaccharides. Thus, the peach surface exhibits a quasi-superhydrophobic property and high adhesive force. A water droplet on the surface of a peach is a quasi-sphere, which is unable to roll off even when the peach is turned upside down. This is defined as the peach skin effect. We present that the quasi-superhydrophobic state with high adhesive force is attributed to the special coexisting Wenzel＇s and Cassie＇s state for water droplets, thus creating the strong interaction between the water droplet and surface.展开更多
Annulus fibrosus(AF)plays a crucial role in the biomechanical loading of intervertebral disc(IVD).AF is difficult to self-heal when the annulus tears develop,because AF has a unique intricate structure and biologic mi...Annulus fibrosus(AF)plays a crucial role in the biomechanical loading of intervertebral disc(IVD).AF is difficult to self-heal when the annulus tears develop,because AF has a unique intricate structure and biologic milieu in vivo.Tissue engineering is promising for repairing AF rupture,but construction of suitable mechanical matching devices or scaffolds is still a grand challenge.To deeply know the varied forces involved in the movement of the native annulus is highly beneficial for designing biomimetic scaffolds to recreate the AF function.In this review,we overview six freedom degrees of forces and adhesion strength on AF tissue.Then,we summarize the mechanical modalities to simulate related forces on AF and to assess the characteristics of biomaterials.We finally outline some current advanced techniques to develop mechanically adaptable biomaterials for AF rupture repair.展开更多
基金supported by the National Natural Science Foundation of China(No.52475580)the Special Foundation of the Taishan Scholar Project(No.tsqn202211077)+3 种基金the Shandong Provincial Natural Science Foundation(No.ZR2023ME118)the Open Project of State Key Laboratory of Chemical Safety(No.SKLCS-2024020)the Fundamental Research Funds for the Central Universities(No.24CX02014A)the Fund of State Key Laboratory of Deep Oil and Gas,China University of Petroleum(East China).
文摘In the context of the rapid development of artificial intelligence and robotics,their application scenarios are continuously expanding to a variety of complex environments,with increasing attention being paid to the use of flexible sensors in lowtemperature environments.In this study,an ionic hydrogel was synthesized using acrylamide(AM),hydroxyethyl cellulose(HEC),and lithium chloride(LiCl)as composites.This hydrogel exhibits high adhesion,excellent sensitivity(gauge factor(GF)=2.84),rapid response time(100 ms),exceptional stretch ability(>1776%),high toughness(2.5 MJ/m^(3)),and the ability to maintain detectability at low temperatures(-60℃).HEC imparts reliable mechanical properties to the sensor through hydrogen bonding interactions of its hydroxyl groups.LiCl ensures that the sensor has outstanding antifreezing properties,maintains good conductivity and mechanical performance.Used for robotic attitude detection,the sensor demonstrated accurate recognition of various joint movements at both 20 and -20℃.This technology was extended to industrial operations and maintenance,where a mechanical claw was used to grasp parts at both room temperature and low temperature.A convolutional neural network deep learning algorithm was employed to identify and classify eight types of parts,achieving an impressive recognition accuracy of 98.8%.The polyacrylamide(PAM)/HEC/LiCl hydrogel sensor demonstrates the capability for wide-temperature range detection in flexible robotics,holding significant potential for future applications in human-machine interaction,tactile perception,and related fields.
基金supported by the National Key R&D Program of China(Grant No.2021YFA0719200)the National Natural Science Foundation of China(Grant Nos.12272391,12232020,and 11672314)the CAS Project for Young Scientists in Basic Research(Grant No.YSBR-096).
文摘It is a challenge to determine the dominant topological characteristics of mechanical properties of adhesive interfaces.In this paper,we used graph theory and molecular dynamics simulation to investigate the influence of topological characteristics on the strength and toughness of highly cross-linked polymer interface systems.Based on the microstructure of the adhesive system,we extracted the dominant topological characteristics,including the connectivity degree(D)that determines the yield strength,and the average node-path(P)and the simple cycles proportions(R)that determine the deformability and load-bearing capacity during the void propagation respectively,which co-determine the toughness.The influence of the wall-effect on the dominant topological characteristics was also analyzed.The results showed that the interfacial yield strength increases with the increase of D,while the toughness increases with the increase of P and R.The wall-effect has a significant influence on D,P,and R.The strong wall-effect causes the enrichment of amino groups near the wall and insufficient cross-linking away from the wall,leading to the lower D and R,i.e.,the lower yield strength and load-bearing capacity during the void propagation.With the attenuation of the wall-effect,the D increases gradually,while the P and the R first increase and then decrease,showing an optimized wall-effect for the toughness of the adhesive interface.This paper reveals the dominant topological characteristics of adhesive interfacial strength and toughness,providing a new way to modulate the mechanical properties of polymer adhesive interface systems.
基金financially supported by the National Natural Science Foundation of China (Nos.U1909220 and 52003283)Science and Technology Innovation 2025 Major Project of Ningbo (Nos.2021Z092, 2022Z111 and 2022Z160)+1 种基金Defense Industrial Technology Development Program (No.JCKY2021513B001)the Research Project of Technology Application for Public Welfare of Ningbo City (No.202002N3122)。
文摘It is of great significance to design epoxy coatings with superior antibacterial properties and high adhesive properties, as well as excellent processing, superior durability, and high transparency. However, it is still a challenge because of the common complex design and synthesis. Herein, the bio-based monomer protocatechuic acid(PCA) was used as raw material, the catechol structure with high bonding and antibacterial properties was introduced into the flexible alkane segment of ethylene glycol diglycidyl ether(EGDE) through an efficient, and green method, and it was cured with isophorone diamine(IPDA) to prepare corresponding thermosets. The cured resins exhibited excellent allaround qualities, particularly in bonding and antibacterial. When 30% PCA was added to pure epoxy resin, the adhesion between substrate and coating increased from 4.40 MPa to 13.60 MPa and the antibacterial rate of coating against E. coli and S. aureus could approach 100%. All of this is due to the fact that the catechol structure present in PCA has the ability to interact with various substrates and alter the permeability of bacterial cell membranes. The architecture of this method offers a fresh approach to dealing with the issues of challenging raw material selection and complex synthesis techniques.
基金supported by the National Natural Science Foundation of China(21103006)the Beijing Natural Science Foundation(2132030)+2 种基金the National High Technology Research and Development Program of China(2012AA030305)the Fundamental Research Funds for the Central Universities(YWF-10-01-B16,YWF-11-03-Q-214,YWF-13-DX-XYJL-004)the 111 Project(B14009)
文摘The surface of a peach is known to exhibit spe- cial wettability and adhesion behaviors. We disclose that the peach surface is covered with long and short indumentums. The long indumentums are covered mainly with hydrophobic wax molecules, while the short indumentums are coated mostly with hydrophilic polysaccharides. Thus, the peach surface exhibits a quasi-superhydrophobic property and high adhesive force. A water droplet on the surface of a peach is a quasi-sphere, which is unable to roll off even when the peach is turned upside down. This is defined as the peach skin effect. We present that the quasi-superhydrophobic state with high adhesive force is attributed to the special coexisting Wenzel＇s and Cassie＇s state for water droplets, thus creating the strong interaction between the water droplet and surface.
基金support for the work from the Ministry of Science and Technology of China(2020YFA0908900)National Natural Science Foundation of China(21935011 and 21725403)+2 种基金Shenzhen Science and Technology Innovation Commission(KQTD20200820113012029 and JCYJ20220818100601003)Guangdong Basic and Applied Basic Research Foundation(2022A1515110321)Guangdong Provincial Key Laboratory of Advanced Biomaterials(2022B1212010003).
文摘Annulus fibrosus(AF)plays a crucial role in the biomechanical loading of intervertebral disc(IVD).AF is difficult to self-heal when the annulus tears develop,because AF has a unique intricate structure and biologic milieu in vivo.Tissue engineering is promising for repairing AF rupture,but construction of suitable mechanical matching devices or scaffolds is still a grand challenge.To deeply know the varied forces involved in the movement of the native annulus is highly beneficial for designing biomimetic scaffolds to recreate the AF function.In this review,we overview six freedom degrees of forces and adhesion strength on AF tissue.Then,we summarize the mechanical modalities to simulate related forces on AF and to assess the characteristics of biomaterials.We finally outline some current advanced techniques to develop mechanically adaptable biomaterials for AF rupture repair.
