Polymer nanocomposites(PNCs)usually have superior properties than pristine polymers.Understanding the dynamics properties in PNC system is crucial to reveal the mechanism of property change unpon the addition of nanop...Polymer nanocomposites(PNCs)usually have superior properties than pristine polymers.Understanding the dynamics properties in PNC system is crucial to reveal the mechanism of property change unpon the addition of nanoparticles(NPs),and therefore for a better design of the material properties.In this short perspective,we summarize recent advances mainly from theoretical and simulation studies of dynamics properties in polymer nanocomposite system.One is the"vehicle model"which reveals that diffusion dynamics of sticky NP is coupled to surrounding chain segments.Similarly,recent simulations demonstrate that such coupling also exists in all-polymer nanocomposite wich is composed of linear polymer chains and single-chain nanoparticles(SCNPs).These SCNPs have almost the same chemical composition as the matrix chain.Therefore,it is assumed that such all-polymer nanocomposite can act as a model system where there are no enthalpic interactions between NPs and polymer chains.Although the above dynamic coupling was found in the above two different systems containing inorganic NPs or relatively small organic SCNPs,it was found that the length scale of such dynamic coupling(the thickness of the matrix/NP interface)is comparable to the NP size,which is surprisingly consistent in the above two different systems.In addition,a chain-length dependence of the NP influence on the chain dynamics reported from a recent joint simulaiton and experimental study of all-polymer nanocomposite system,and a theoretical model developed for such phenomena are also reviewed.At the end,we give an outlook of this field,especially for possible chainlength dependence of complex dynamics in sticky-NP systems.展开更多
In this work,the single-chain elasticity of polyformaldehyde(POM)is studied,for the first time,by employing atomic force microscopy(AFM)-based single molecule force spectroscopy(SMFS).We find that the single-chain ela...In this work,the single-chain elasticity of polyformaldehyde(POM)is studied,for the first time,by employing atomic force microscopy(AFM)-based single molecule force spectroscopy(SMFS).We find that the single-chain elasticity of POM in a nonpolar organic solvent(nonane)can be described well by a theoretical model(QM-FRC model),when the rotating unit length is 0.144 nm(C―O bond length).After comparison,POM is more flexible than polystyrene(a typical polymer with C―C backbone)at the single-chain level,which is reasonable since the C―O bond has a lower rotation barrier than C―C bond.This result indicates that the flexibility of a polymer chain can be tuned by the C―O bond proportion in backbone,which casts new light on the rational design of new synthetic polymers in the future.展开更多
NAS preparation, a kind of Chinese herbal medicine found by the Yunnan Eco-agricultural Research Institute, has potential antiviral activity. In this paper, the inhibiting effect of NAS preparation on H9N2 subtype Avi...NAS preparation, a kind of Chinese herbal medicine found by the Yunnan Eco-agricultural Research Institute, has potential antiviral activity. In this paper, the inhibiting effect of NAS preparation on H9N2 subtype Avian influenza virus (AIV) was investigated in vivo. Chickens infected with H9N2 virus were treated with NAS preparation for 4 days. The virus was then detected by hemoagglutination (HA) test and reverse transcription polymerase chain reaction (RT-PCR). The results showed that no H9N2 virus could be detected at the 7th day when the chickens were treated with 0.2g/kg/d or 0.1g/kg/d of NAS preparation. However the virus could be detected in other chickens without NAS preparation treatment. This result suggested that NAS preparation may be a potential drug candidate to control infection of H9N2 subtype AIV in chickens.展开更多
Assembling of a few particles into a cluster commonly occurs in many systems.However,it is still challenging to precisely control particle assembling,due to the various amorphous structures induced by thermal fluctuat...Assembling of a few particles into a cluster commonly occurs in many systems.However,it is still challenging to precisely control particle assembling,due to the various amorphous structures induced by thermal fluctuations during cluster formation.Although these structures may have very different degrees of aggregation,a quantitative method is lacking to describe them,and how these structures evolve remains unclear.Therefore a significant step towards precise control of particle self-assembly is to describe and analyze various aggregation structures during cluster formation quantitatively.In this work,we are motivated to propose a method to directly count and quantitatively compare different aggregated structures.We also present several case studies to evaluate how the aggregated structures during cluster formation are affected by external controlling factors,e.g.,different interaction ranges,interaction strengths,or anisotropy of attraction.展开更多
Synthetic polymer single-chain nanoparticles(SCNPs)are an emerging new class of nanomaterials that possess similar folded structures as natural proteins.However,most SCNPs reported so far are packed loosely in their i...Synthetic polymer single-chain nanoparticles(SCNPs)are an emerging new class of nanomaterials that possess similar folded structures as natural proteins.However,most SCNPs reported so far are packed loosely in their interior,resembling those of intrinsically disordered proteins(IDPs).Here,we report a facile strategy to synthesize SCNPs with controllable folding in aqueous solution.展开更多
It was investigated that the domain growth processes of spinodal decomposition with different quenching depth in two and three dimensional binary immiscible fluids by using parallel dissipative particle dynamics simul...It was investigated that the domain growth processes of spinodal decomposition with different quenching depth in two and three dimensional binary immiscible fluids by using parallel dissipative particle dynamics simulations. In two dimensions, the dynamic scaling exponent 1/2 for coalescence and 2/3 for inertial regimes in the shallow quench and strong finite size effects in the cases of deep quenching were obtained. In three dimensions, it was used that the diffusive regime with exponent n=l/3 in the shallow quench and the inertial hydrodynamic regime with n=2/3 for different quenches. The viscous effects are not clearly reflected, showing n=1/2 in both shallow and deep quenches in this time period, due to the soft nature of interaction potential adopted in dissipative particle dynamics.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.21873040,22133002 and 21833008)support from the Program for JLU Science and Technology Innovative Research Team。
文摘Polymer nanocomposites(PNCs)usually have superior properties than pristine polymers.Understanding the dynamics properties in PNC system is crucial to reveal the mechanism of property change unpon the addition of nanoparticles(NPs),and therefore for a better design of the material properties.In this short perspective,we summarize recent advances mainly from theoretical and simulation studies of dynamics properties in polymer nanocomposite system.One is the"vehicle model"which reveals that diffusion dynamics of sticky NP is coupled to surrounding chain segments.Similarly,recent simulations demonstrate that such coupling also exists in all-polymer nanocomposite wich is composed of linear polymer chains and single-chain nanoparticles(SCNPs).These SCNPs have almost the same chemical composition as the matrix chain.Therefore,it is assumed that such all-polymer nanocomposite can act as a model system where there are no enthalpic interactions between NPs and polymer chains.Although the above dynamic coupling was found in the above two different systems containing inorganic NPs or relatively small organic SCNPs,it was found that the length scale of such dynamic coupling(the thickness of the matrix/NP interface)is comparable to the NP size,which is surprisingly consistent in the above two different systems.In addition,a chain-length dependence of the NP influence on the chain dynamics reported from a recent joint simulaiton and experimental study of all-polymer nanocomposite system,and a theoretical model developed for such phenomena are also reviewed.At the end,we give an outlook of this field,especially for possible chainlength dependence of complex dynamics in sticky-NP systems.
基金the National Natural Science Foundation of China(No.21774102).
文摘In this work,the single-chain elasticity of polyformaldehyde(POM)is studied,for the first time,by employing atomic force microscopy(AFM)-based single molecule force spectroscopy(SMFS).We find that the single-chain elasticity of POM in a nonpolar organic solvent(nonane)can be described well by a theoretical model(QM-FRC model),when the rotating unit length is 0.144 nm(C―O bond length).After comparison,POM is more flexible than polystyrene(a typical polymer with C―C backbone)at the single-chain level,which is reasonable since the C―O bond has a lower rotation barrier than C―C bond.This result indicates that the flexibility of a polymer chain can be tuned by the C―O bond proportion in backbone,which casts new light on the rational design of new synthetic polymers in the future.
基金Key Technologies Research and Development Program (2004BA519A26)
文摘NAS preparation, a kind of Chinese herbal medicine found by the Yunnan Eco-agricultural Research Institute, has potential antiviral activity. In this paper, the inhibiting effect of NAS preparation on H9N2 subtype Avian influenza virus (AIV) was investigated in vivo. Chickens infected with H9N2 virus were treated with NAS preparation for 4 days. The virus was then detected by hemoagglutination (HA) test and reverse transcription polymerase chain reaction (RT-PCR). The results showed that no H9N2 virus could be detected at the 7th day when the chickens were treated with 0.2g/kg/d or 0.1g/kg/d of NAS preparation. However the virus could be detected in other chickens without NAS preparation treatment. This result suggested that NAS preparation may be a potential drug candidate to control infection of H9N2 subtype AIV in chickens.
文摘Assembling of a few particles into a cluster commonly occurs in many systems.However,it is still challenging to precisely control particle assembling,due to the various amorphous structures induced by thermal fluctuations during cluster formation.Although these structures may have very different degrees of aggregation,a quantitative method is lacking to describe them,and how these structures evolve remains unclear.Therefore a significant step towards precise control of particle self-assembly is to describe and analyze various aggregation structures during cluster formation quantitatively.In this work,we are motivated to propose a method to directly count and quantitatively compare different aggregated structures.We also present several case studies to evaluate how the aggregated structures during cluster formation are affected by external controlling factors,e.g.,different interaction ranges,interaction strengths,or anisotropy of attraction.
基金supported by the National Natural Science Foundation of China(nos.21873040 and 21534004).
文摘Synthetic polymer single-chain nanoparticles(SCNPs)are an emerging new class of nanomaterials that possess similar folded structures as natural proteins.However,most SCNPs reported so far are packed loosely in their interior,resembling those of intrinsically disordered proteins(IDPs).Here,we report a facile strategy to synthesize SCNPs with controllable folding in aqueous solution.
基金This work was supported by the National Natural Science Foundation of China （No.20774036） and the Fok Ying Tung Education Foundation （No.114018）.
文摘It was investigated that the domain growth processes of spinodal decomposition with different quenching depth in two and three dimensional binary immiscible fluids by using parallel dissipative particle dynamics simulations. In two dimensions, the dynamic scaling exponent 1/2 for coalescence and 2/3 for inertial regimes in the shallow quench and strong finite size effects in the cases of deep quenching were obtained. In three dimensions, it was used that the diffusive regime with exponent n=l/3 in the shallow quench and the inertial hydrodynamic regime with n=2/3 for different quenches. The viscous effects are not clearly reflected, showing n=1/2 in both shallow and deep quenches in this time period, due to the soft nature of interaction potential adopted in dissipative particle dynamics.
