The size effect of the polydopamine(PDA)-coated BaTiO_(3)(BTO)(BTO@PDA)nanoparticles(NPs)on the interfacial compatibility between BTO NPs and the polymer matrix and the resultant piezoelectric performance of the compo...The size effect of the polydopamine(PDA)-coated BaTiO_(3)(BTO)(BTO@PDA)nanoparticles(NPs)on the interfacial compatibility between BTO NPs and the polymer matrix and the resultant piezoelectric performance of the composite films remain elusive.In this study,BTO and BTO@PDA NPs of various sizes were incorporated into a P(VDF-TrFE)matrix to prepare two series of P(VDF-TrFE)/BTO and P(VDF-TrFE)/BTO@PDA composites.Subsequently,the effects of the NP size on the dielectric,ferroelectric,and piezoelectric properties of the composite films were comprehensively studied.As the size of the BTO@PDA NPs increased,residual hole defects were clearly observed in the cross section of the composite film.The deteriorated interfacial compatibility due to the large size of the BTO@PDA NPs was also confirmed by the increased dielectric permittivity of the composite film,which was induced by the intensified interfacial polarisation.The P(VDF-TrFE)/BTO@PDA composite with NPs of the smallest size(100 nm)exhibited superior piezoelectric performance owing to the excellent interfacial compatibility between the fillers and the matrix.The piezoelectric performance was significantly enhanced by the reduced leakage current during electrical poling and reduced trap charges.Finally,the pulse waveform originating from the radial artery was precisely measured using the optimised P(VDF-TrFE)/BTO@PDA composite film.展开更多
We report a high-throughput and label-free computational imaging technique that simultaneously measures in three-dimensional(3D)space the locomotion and angular spin of the freely moving heads of microswimmers and the...We report a high-throughput and label-free computational imaging technique that simultaneously measures in three-dimensional(3D)space the locomotion and angular spin of the freely moving heads of microswimmers and the beating patterns of their flagella over a sample volume more than two orders-of-magnitude larger compared to existing optical modalities.Using this platform,we quantified the 3D locomotion of 2133 bovine sperms and determined the spin axis and the angular velocity of the sperm head,providing the perspective of an observer seated at the moving and spinning sperm head.In this constantly transforming perspective,flagellum-beating patterns are decoupled from both the 3D translation and spin of the head,which provides the opportunity to truly investigate the 3D spatio-temporal kinematics of the flagellum.In addition to providing unprecedented information on the 3D locomotion of microswimmers,this computational imaging technique could also be instrumental for micro-robotics and sensing research,enabling the high-throughput quantification of the impact of various stimuli and chemicals on the 3D swimming patterns of sperms,motile bacteria and other micro-organisms,generating new insights into taxis behaviors and the underlying biophysics.展开更多
基金This work was supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.2022R1F1A107172011).
文摘The size effect of the polydopamine(PDA)-coated BaTiO_(3)(BTO)(BTO@PDA)nanoparticles(NPs)on the interfacial compatibility between BTO NPs and the polymer matrix and the resultant piezoelectric performance of the composite films remain elusive.In this study,BTO and BTO@PDA NPs of various sizes were incorporated into a P(VDF-TrFE)matrix to prepare two series of P(VDF-TrFE)/BTO and P(VDF-TrFE)/BTO@PDA composites.Subsequently,the effects of the NP size on the dielectric,ferroelectric,and piezoelectric properties of the composite films were comprehensively studied.As the size of the BTO@PDA NPs increased,residual hole defects were clearly observed in the cross section of the composite film.The deteriorated interfacial compatibility due to the large size of the BTO@PDA NPs was also confirmed by the increased dielectric permittivity of the composite film,which was induced by the intensified interfacial polarisation.The P(VDF-TrFE)/BTO@PDA composite with NPs of the smallest size(100 nm)exhibited superior piezoelectric performance owing to the excellent interfacial compatibility between the fillers and the matrix.The piezoelectric performance was significantly enhanced by the reduced leakage current during electrical poling and reduced trap charges.Finally,the pulse waveform originating from the radial artery was precisely measured using the optimised P(VDF-TrFE)/BTO@PDA composite film.
基金the support of the Presidential Early Career Award for Scientists and Engineers(PECASE)the Army Research Office(ARO,W911NF-13-1-0419 and W911NF-13-1-0197)+11 种基金the ARO Life Sciences Divisionthe National Science Foundation(NSF)CBET Division Biophotonics Programthe NSF Emerging Frontiers in Research and Innovation(EFRI)Awardthe NSF EAGER Award,NSF INSPIRE Award,NSF Partnerships for Innovation:Building Innovation Capacity(PFI:BIC)ProgramOffice of Naval Research(ONR)the National Institutes of Health(NIH)the Howard Hughes Medical Institute(HHMI)Vodafone Americas Foundationthe Mary Kay FoundationSteven&Alexandra Cohen Foundation,and KAUSTbased upon research performed in a laboratory renovated by the National Science Foundation under Grant No.0963183award funded under the American Recovery and Reinvestment Act of 2009(ARRA).
文摘We report a high-throughput and label-free computational imaging technique that simultaneously measures in three-dimensional(3D)space the locomotion and angular spin of the freely moving heads of microswimmers and the beating patterns of their flagella over a sample volume more than two orders-of-magnitude larger compared to existing optical modalities.Using this platform,we quantified the 3D locomotion of 2133 bovine sperms and determined the spin axis and the angular velocity of the sperm head,providing the perspective of an observer seated at the moving and spinning sperm head.In this constantly transforming perspective,flagellum-beating patterns are decoupled from both the 3D translation and spin of the head,which provides the opportunity to truly investigate the 3D spatio-temporal kinematics of the flagellum.In addition to providing unprecedented information on the 3D locomotion of microswimmers,this computational imaging technique could also be instrumental for micro-robotics and sensing research,enabling the high-throughput quantification of the impact of various stimuli and chemicals on the 3D swimming patterns of sperms,motile bacteria and other micro-organisms,generating new insights into taxis behaviors and the underlying biophysics.
