In this paper, tin disulfide （SnS2）, a two-dimensional （2D） n-type direct bandgap layered metal dichalcogenide with a gap value of 2.24 eV, was employed as a saturable absorber. Its appearance and nonlinear satura...In this paper, tin disulfide （SnS2）, a two-dimensional （2D） n-type direct bandgap layered metal dichalcogenide with a gap value of 2.24 eV, was employed as a saturable absorber. Its appearance and nonlinear saturable ab- sorption characteristics were also investigated experimentally. SnSz-PVA （polyvinyl alcohol） film was successfully prepared and employed as a mode-locker for achieving a mode-locked Er-doped fiber laser with a pulse width of 623 fs at a pulse repetition rate of 29.33 MHz. The results prove that SnS2 nanosheets will have wide potential ultrafast photonic applications due to their suitable bandgap value and excellent nonlinear saturable absorption characteristics.展开更多
Summary of main observation and conclusion Stimuli-responsive hydrogels crosslinked by weak noncovalent bonds such as hydrogen bonds,ionic interactions,host-guest interactions and hydrophobic interactions have been ex...Summary of main observation and conclusion Stimuli-responsive hydrogels crosslinked by weak noncovalent bonds such as hydrogen bonds,ionic interactions,host-guest interactions and hydrophobic interactions have been extensively investigated.Herein,azobenzene and spiropyran acting as two hydrophobic pendant groups were introduced into a hydrophilic polyacrylamide (PAM) via free radical copolymerization to construct a hydrophobic interaction based thermo-,light-responsive polymer hydrogel.Its viscosity and color could be reversibly regulated by heating and cooling.Meanwhile,its color could be specifically switched by light without obvious viscosity change.The gel was also capable of being transited to sol by addition of β-cyclodextrin (β-CD),which encaged the hydrophobic groups and then increased the solubility of polymer in water.The hydrogel could be regained after UV irradiation at λ=365 nm,and after irradiation at λ=440 nm,the hydrogel changed into a clear sol again.展开更多
Construction of supramolecular polymers, in which functional monomer components are held together by non- covalent interactions, is considered as a promising design principle for functional materials. Linear fluoresce...Construction of supramolecular polymers, in which functional monomer components are held together by non- covalent interactions, is considered as a promising design principle for functional materials. Linear fluorescent su- pramolecular polymer assembled on account of electrostatic attractions based host-guest interaction is synthesized and illustrated here. 1H NMR was involved to ensure the structure of guest and polymer, UV-vis and fluorescent spectra were recorded to be a readout signal to investigate the assemble process of polymer. TEM and AFM meas- urements were carried out to confirm the homogeneous nanometer-sized molecular assembly. It shows the way to be used as remote readout fluorescent functional material in the future.展开更多
基金National Natural Science Foundation of China(NSFC)(11474187,61205174,61475089)China Postdoctoral Science Foundation(2016M602177)Natural Science Foundation of Shandong Province,China(ZR2014FM028,ZR2016FP01)
文摘In this paper, tin disulfide （SnS2）, a two-dimensional （2D） n-type direct bandgap layered metal dichalcogenide with a gap value of 2.24 eV, was employed as a saturable absorber. Its appearance and nonlinear saturable ab- sorption characteristics were also investigated experimentally. SnSz-PVA （polyvinyl alcohol） film was successfully prepared and employed as a mode-locker for achieving a mode-locked Er-doped fiber laser with a pulse width of 623 fs at a pulse repetition rate of 29.33 MHz. The results prove that SnS2 nanosheets will have wide potential ultrafast photonic applications due to their suitable bandgap value and excellent nonlinear saturable absorption characteristics.
基金the National Natural Science Foundation of China (No.21402053)State Key Laboratory of Molecular Engineering of Polymers (Fudan University)(K2018-20) for financial support of this study.
文摘Summary of main observation and conclusion Stimuli-responsive hydrogels crosslinked by weak noncovalent bonds such as hydrogen bonds,ionic interactions,host-guest interactions and hydrophobic interactions have been extensively investigated.Herein,azobenzene and spiropyran acting as two hydrophobic pendant groups were introduced into a hydrophilic polyacrylamide (PAM) via free radical copolymerization to construct a hydrophobic interaction based thermo-,light-responsive polymer hydrogel.Its viscosity and color could be reversibly regulated by heating and cooling.Meanwhile,its color could be specifically switched by light without obvious viscosity change.The gel was also capable of being transited to sol by addition of β-cyclodextrin (β-CD),which encaged the hydrophobic groups and then increased the solubility of polymer in water.The hydrogel could be regained after UV irradiation at λ=365 nm,and after irradiation at λ=440 nm,the hydrogel changed into a clear sol again.
基金This work is supported by the National Natural Sci- ence Foundation of China （No. 21402053） and China Postdoctoral Science Foundation （Nos. 2014M56031g, 2015T80414）.
文摘Construction of supramolecular polymers, in which functional monomer components are held together by non- covalent interactions, is considered as a promising design principle for functional materials. Linear fluorescent su- pramolecular polymer assembled on account of electrostatic attractions based host-guest interaction is synthesized and illustrated here. 1H NMR was involved to ensure the structure of guest and polymer, UV-vis and fluorescent spectra were recorded to be a readout signal to investigate the assemble process of polymer. TEM and AFM meas- urements were carried out to confirm the homogeneous nanometer-sized molecular assembly. It shows the way to be used as remote readout fluorescent functional material in the future.
