In the fields of electronic skin and soft wearable sensors,intrinsically stretchable conductors undergo rapid development;however,practical applications of artificial skinlike materials/devices have not been realized ...In the fields of electronic skin and soft wearable sensors,intrinsically stretchable conductors undergo rapid development;however,practical applications of artificial skinlike materials/devices have not been realized because of the difficulty in combining the electromechanical properties and sensing performance.Contrarily,insoluble inorganic conductive domains in the hydrogel matrix are generally incompatible with surrounding elastic networks,decreasing the mechanical strength.Usually,the hydrogels are vulnerable either to severe mechanical stimuli or large deformation,especially when notches are induced.In this study,based on an energy-dissipative dual-crosslinked conductive hydrogel,a mechanically durable and super-tough strain sensor was developed.The highly soft yet dynamically tough hydrogel demonstrated high ionic conductivity(30.2 mS cm^(-1)),ultrastretchability(>600%strain),and superior linear dependence of strain sensitivity with a maximum gauge factor of 1.2 at 500%strain.Because of these advantageous synergistic effects,the resultant hydrogel strain sensor demonstrated reliable and stable detection of a large range of human motion and subtle vibrations.Moreover,it impressively exhibited super toughness that could endure consecutive treading pressure and even retain normal operation after 20 times of car run-over on the road.These demonstrations highly confirm the sensor’s superior mechanical durability and reliability,displaying great potential in developing next-generation mechanically adaptable sensors.展开更多
Polyamide/acrylonitrile-butadiene-styrene copolymer(PA/ABS) blends have drawn considerable attention from both academia and industry for their important applications in automotive and electronic areas. Due to poor mis...Polyamide/acrylonitrile-butadiene-styrene copolymer(PA/ABS) blends have drawn considerable attention from both academia and industry for their important applications in automotive and electronic areas. Due to poor miscibility of PA and ABS, developing an effective compatibilization strategy has been an urgent challenge to achieve prominent mechanical properties. In this study, we create a set of mechanically enhanced PA6/ABS blends using two multi-monomer melt-grafted compatibilizers, SEBSg-(MAH-co-St) and ABS-g-(MAH-co-St). The dispersed domain size is significantly decreased and meanwhile the unique "soft shell-encapsulating-hard core" structures form in the presence of compatibilizers. The optimum mechanical performances manifest an increase of 36% in tensile strength and an increase of 1300% in impact strength, compared with the neat PA6/ABS binary blend.展开更多
It is a challenge to develop a biodegradable toughener to toughen polylactic acid(PLA)with both high strength and high toughness,since toughness and strength are mutually exclusive.Here,a series of supertough polyeste...It is a challenge to develop a biodegradable toughener to toughen polylactic acid(PLA)with both high strength and high toughness,since toughness and strength are mutually exclusive.Here,a series of supertough polyester thermoplastic elastomers(TPEs),poly(L/D-lactide)-b-poly(ε-caprolactone-co-δ-valerolactone)-b-poly(L/D-lactide)s(PLLA-PCVL-PLLA,L-TPEs or PDLA-PCVL-PDLA,D-TPEs),were prepared and blended with a PLLA matrix to toughen PLLA.The mechanical properties of PLLA could be regulated in a wide range by changing blending ratios and TPE structures.For PLLA blends toughened by L-TPEs,the highest elongation at break is up to 425%with the tensile strength of 33.1 MPa and the toughness of 104 MJ/m3.By the stereocomplex crystallization of PLA(sc-PLA),the tensile strength of the PLLA/D-TPE blends further increased to 41.8 MPa with a similar elongation at break(418%)and the toughness up to 128 MJ/m3.The detailed characterizations revealed a toughening mechanism:(I)the added soft segments increased the ductility of the PLLA matrix,(II)the PLLA segments of L-TPEs increased the compatibility between TPEs and PLLA matrix,and(III)the formation of sc-PLA between the PDLA segments in D-TPE and PLLA provided higher tensile strength by enhancing the strength of the crystal skeleton.The toughened PLA using TPEs can maintain original non-toxic and degradable properties,and be applied potentially in surgical sutures,and 3D-printed scaffolds.展开更多
Hydrogel-based quasi-solid-state electrolytes(Q-SSEs) swollen with electrolyte solutions are important components in stretchable supercapacitors and other wearable devices. This work fabricates a supertough, fatigue-r...Hydrogel-based quasi-solid-state electrolytes(Q-SSEs) swollen with electrolyte solutions are important components in stretchable supercapacitors and other wearable devices. This work fabricates a supertough, fatigue-resistant, and alkali-resistant multi-bond network(MBN) hydrogel aiming to be an alkaline Q-SSE. To synthesize the hydrogel, a 2-ureido-4[1H]-pyrimidone(UPy) motif is introduced into a poly(acrylic acid) polymer chain. The obtained MBN hydrogels with 75 wt% water content exhibit tensile strength as high as 2.47 MPa, which is enabled by the large energy dissipation ability originated from the dissociation of UPy dimers due to their high bond association energy. Owing to the high dimerization constant of UPy motifs, the dissociated UPy motifs are able to partially re-associate soon after being released from external forces, resulting in excellent fatigue-resistance. More importantly, the MBN hydrogels exhibit excellent alkali-resistance ability. The UPy Gel-10 swollen with 1 mol/L KOH display a tensile strength as high as ~1.0 MPa with elongation at break of ~550%. At the same time, they show ionic conductivity of ~17 m S/cm, which do not decline even when the hydrogels are stretched to 500% strain.The excellent mechanical property and ionic conductivity of the present hydrogels demonstrate potential application as a stretchable alkaline Q-SSE.展开更多
Multi-bond network(MBN) hydrogels contain hierarchical dynamic bonds with different bond association energy as energy dissipation units,enabling super-tough mechanical properties.In this work,we copolymerize a protona...Multi-bond network(MBN) hydrogels contain hierarchical dynamic bonds with different bond association energy as energy dissipation units,enabling super-tough mechanical properties.In this work,we copolymerize a protonated 2-ureido-4[1 H]-pyrimidone(UPy)-contained monomer with acrylic acid in HCl solution.After removing excess HCl,UPy motifs are deprotonated and from dimers,thus generating an UPy-contained MBN hydrogel.The obtained MBN hydrogels(75 wt% watercontent) exhibit super-tough mechanical properties(0.39 MPa to 2.51 MPa tensile strength),with tremendous amount of energy(1.68 MJ/m^(3) to 11.1 MJ/m^(3)) dissipated by the dissociation of UPy dimers.The introduction of ionic bonds can further improve the mechanical properties.Moreover,owing to their dynamic nature,both UPy dimers and ionic bonds can re-associate after being dissociated,resulting in excellent self-recovery ability(around 90% recovery efficiency within only 1 h).The excellent self-recovery ability mainly originates from the re-association of UPy dimers based on the high dimerization constant of UPy motifs.展开更多
基金the Science Technology and Innovation Committee of Shenzhen Municipality under Shenzhen Technology Project(JSGG20180508151728414)the Department of Science and Technology of Guangdong Province under Guangdong Science and Technology Project(2018B020208001)。
文摘In the fields of electronic skin and soft wearable sensors,intrinsically stretchable conductors undergo rapid development;however,practical applications of artificial skinlike materials/devices have not been realized because of the difficulty in combining the electromechanical properties and sensing performance.Contrarily,insoluble inorganic conductive domains in the hydrogel matrix are generally incompatible with surrounding elastic networks,decreasing the mechanical strength.Usually,the hydrogels are vulnerable either to severe mechanical stimuli or large deformation,especially when notches are induced.In this study,based on an energy-dissipative dual-crosslinked conductive hydrogel,a mechanically durable and super-tough strain sensor was developed.The highly soft yet dynamically tough hydrogel demonstrated high ionic conductivity(30.2 mS cm^(-1)),ultrastretchability(>600%strain),and superior linear dependence of strain sensitivity with a maximum gauge factor of 1.2 at 500%strain.Because of these advantageous synergistic effects,the resultant hydrogel strain sensor demonstrated reliable and stable detection of a large range of human motion and subtle vibrations.Moreover,it impressively exhibited super toughness that could endure consecutive treading pressure and even retain normal operation after 20 times of car run-over on the road.These demonstrations highly confirm the sensor’s superior mechanical durability and reliability,displaying great potential in developing next-generation mechanically adaptable sensors.
基金the National Natural Science Foundation of China (No. 51633003) for the financial support
文摘Polyamide/acrylonitrile-butadiene-styrene copolymer(PA/ABS) blends have drawn considerable attention from both academia and industry for their important applications in automotive and electronic areas. Due to poor miscibility of PA and ABS, developing an effective compatibilization strategy has been an urgent challenge to achieve prominent mechanical properties. In this study, we create a set of mechanically enhanced PA6/ABS blends using two multi-monomer melt-grafted compatibilizers, SEBSg-(MAH-co-St) and ABS-g-(MAH-co-St). The dispersed domain size is significantly decreased and meanwhile the unique "soft shell-encapsulating-hard core" structures form in the presence of compatibilizers. The optimum mechanical performances manifest an increase of 36% in tensile strength and an increase of 1300% in impact strength, compared with the neat PA6/ABS binary blend.
基金This work was supported by the National Key Research and Development Program of China(No.2022YFB3704900)the National Natural Science Foundation of China(Nos.22225104,22071077,21871107,21975102)the China Postdoctoral Science Foundation(Nos.2022TQ0115,2022M711297).
文摘It is a challenge to develop a biodegradable toughener to toughen polylactic acid(PLA)with both high strength and high toughness,since toughness and strength are mutually exclusive.Here,a series of supertough polyester thermoplastic elastomers(TPEs),poly(L/D-lactide)-b-poly(ε-caprolactone-co-δ-valerolactone)-b-poly(L/D-lactide)s(PLLA-PCVL-PLLA,L-TPEs or PDLA-PCVL-PDLA,D-TPEs),were prepared and blended with a PLLA matrix to toughen PLLA.The mechanical properties of PLLA could be regulated in a wide range by changing blending ratios and TPE structures.For PLLA blends toughened by L-TPEs,the highest elongation at break is up to 425%with the tensile strength of 33.1 MPa and the toughness of 104 MJ/m3.By the stereocomplex crystallization of PLA(sc-PLA),the tensile strength of the PLLA/D-TPE blends further increased to 41.8 MPa with a similar elongation at break(418%)and the toughness up to 128 MJ/m3.The detailed characterizations revealed a toughening mechanism:(I)the added soft segments increased the ductility of the PLLA matrix,(II)the PLLA segments of L-TPEs increased the compatibility between TPEs and PLLA matrix,and(III)the formation of sc-PLA between the PDLA segments in D-TPE and PLLA provided higher tensile strength by enhancing the strength of the crystal skeleton.The toughened PLA using TPEs can maintain original non-toxic and degradable properties,and be applied potentially in surgical sutures,and 3D-printed scaffolds.
基金the National Natural Science Foundation of China (Nos. 21774069, 51633003 and 21474058) for financial support。
文摘Hydrogel-based quasi-solid-state electrolytes(Q-SSEs) swollen with electrolyte solutions are important components in stretchable supercapacitors and other wearable devices. This work fabricates a supertough, fatigue-resistant, and alkali-resistant multi-bond network(MBN) hydrogel aiming to be an alkaline Q-SSE. To synthesize the hydrogel, a 2-ureido-4[1H]-pyrimidone(UPy) motif is introduced into a poly(acrylic acid) polymer chain. The obtained MBN hydrogels with 75 wt% water content exhibit tensile strength as high as 2.47 MPa, which is enabled by the large energy dissipation ability originated from the dissociation of UPy dimers due to their high bond association energy. Owing to the high dimerization constant of UPy motifs, the dissociated UPy motifs are able to partially re-associate soon after being released from external forces, resulting in excellent fatigue-resistance. More importantly, the MBN hydrogels exhibit excellent alkali-resistance ability. The UPy Gel-10 swollen with 1 mol/L KOH display a tensile strength as high as ~1.0 MPa with elongation at break of ~550%. At the same time, they show ionic conductivity of ~17 m S/cm, which do not decline even when the hydrogels are stretched to 500% strain.The excellent mechanical property and ionic conductivity of the present hydrogels demonstrate potential application as a stretchable alkaline Q-SSE.
基金the National Natural Science Foundation of China(Nos.21774069,51633003 and 21474058)for financial support。
文摘Multi-bond network(MBN) hydrogels contain hierarchical dynamic bonds with different bond association energy as energy dissipation units,enabling super-tough mechanical properties.In this work,we copolymerize a protonated 2-ureido-4[1 H]-pyrimidone(UPy)-contained monomer with acrylic acid in HCl solution.After removing excess HCl,UPy motifs are deprotonated and from dimers,thus generating an UPy-contained MBN hydrogel.The obtained MBN hydrogels(75 wt% watercontent) exhibit super-tough mechanical properties(0.39 MPa to 2.51 MPa tensile strength),with tremendous amount of energy(1.68 MJ/m^(3) to 11.1 MJ/m^(3)) dissipated by the dissociation of UPy dimers.The introduction of ionic bonds can further improve the mechanical properties.Moreover,owing to their dynamic nature,both UPy dimers and ionic bonds can re-associate after being dissociated,resulting in excellent self-recovery ability(around 90% recovery efficiency within only 1 h).The excellent self-recovery ability mainly originates from the re-association of UPy dimers based on the high dimerization constant of UPy motifs.
