Molecular Dynamics of Polyrotaxane in Solution Investigated by Quasi-Elastic Neutron Scattering and Molecular Dynamics Simulation: Sliding Motion of Rings on Polymer.

In this study, we investigated the molecular dynamics of polyrotaxane (PR), composed of α-cyclodextrins (CDs) and a poly(ethylene glycol) (PEG) axial chain, in solution by means of quasi-elastic neutron scattering (QENS) measurements and full-atomistic molecular dynamics (MD) simulations. From QENS experiments, we estimated the diffusion coefficients of CD and PEG monomers in PR, which are in quantitative agreement with those obtained by MD simulations. By analyzing the simulation results, we succeeded, for the first time, in observing and quantifying the sliding motion of CD along a PEG chain. The diffusion coefficient for the sliding motion is almost 6 times lower than that of the translational diffusion of CD in PR at room temperature. The retardation of the sliding motion is caused by the energy barrier on PEG produced by molecular interactions between CD and PEG. We propose a simple equation to describe the diffusion coefficient of the sliding dynamics in PR by combining the Einstein-Stokes diffusion model and a one-dimensional jump diffusion model. This work provides a general strategy for the molecular designs to control the sliding motion in PR.

[1]  K. Ito,et al.  Sliding Dynamics of Ring on Polymer in Rotaxane: A Coarse-Grained Molecular Dynamics Simulation Study , 2019, Macromolecules.

[2]  Y. Takashima,et al.  Solvent-Free Photoresponsive Artificial Muscles Rapidly Driven by Molecular Machines. , 2018, Journal of the American Chemical Society.

[3]  K. Ito,et al.  Optically transparent, high-toughness elastomer using a polyrotaxane cross-linker as a molecular pulley , 2018, Science Advances.

[4]  Kazuaki Kato,et al.  Highly Stretchable and Instantly Recoverable Slide-Ring Gels Consisting of Enzymatically Synthesized Polyrotaxane with Low Host Coverage , 2018, Chemistry of Materials.

[5]  Kazuaki Kato,et al.  An efficient synthesis of low-covered polyrotaxanes grafted with poly(ε-caprolactone) and the mechanical properties of its cross-linked elastomers , 2018, Polymer.

[6]  Kazuaki Kato,et al.  Unusual Fracture Behavior of Slide-Ring Gels with Movable Cross-Links. , 2017, ACS macro letters.

[7]  Rina Maeda,et al.  Mechanical properties of supramolecular elastomers prepared from polymer-grafted polyrotaxane , 2017 .

[8]  Berk Hess,et al.  GROMACS: High performance molecular simulations through multi-level parallelism from laptops to supercomputers , 2015 .

[9]  K. Ito,et al.  Extremely stretchable thermosensitive hydrogels by introducing slide-ring polyrotaxane cross-linkers and ionic groups into the polymer network , 2014, Nature Communications.

[10]  Peter M. Kasson,et al.  GROMACS 4.5: a high-throughput and highly parallel open source molecular simulation toolkit , 2013, Bioinform..

[11]  Emile Brabet,et al.  A pH-sensitive lasso-based rotaxane molecular switch. , 2013, Chemistry.

[12]  C. Chipot,et al.  How Do α-Cyclodextrins Self-Organize on a Polymer Chain? , 2012 .

[13]  J. Colmenero,et al.  Single Chain Dynamic Structure Factor of Poly(ethylene oxide) in Dynamically Asymmetric Blends with Poly(methyl methacrylate). Neutron Scattering and Molecular Dynamics Simulations , 2012 .

[14]  K. Ito,et al.  Dynamics of polyrotaxane investigated by neutron spin echo , 2009 .

[15]  Alexander D. MacKerell,et al.  CHARMM Additive All-Atom Force Field for Glycosidic Linkages between Hexopyranoses. , 2009, Journal of chemical theory and computation.

[16]  Akira Harada,et al.  Cyclodextrin-based supramolecular polymers. , 2009, Chemical Society reviews.

[17]  Alexander D. MacKerell,et al.  Additive empirical force field for hexopyranose monosaccharides , 2008, J. Comput. Chem..

[18]  A. Ghoufi,et al.  Quasi-elastic neutron scattering and molecular dynamics study of methane diffusion in metal organic frameworks MIL-47(V) and MIL-53(Cr). , 2008, Angewandte Chemie.

[19]  Alexander D. MacKerell,et al.  Molecular dynamics studies of polyethylene oxide and polyethylene glycol: hydrodynamic radius and shape anisotropy. , 2008, Biophysical journal.

[20]  K. Ito,et al.  Concentration-Induced Conformational Change in Linear Polymer Threaded into Cyclic Molecules , 2008 .

[21]  Carsten Kutzner,et al.  GROMACS 4:  Algorithms for Highly Efficient, Load-Balanced, and Scalable Molecular Simulation. , 2008, Journal of chemical theory and computation.

[22]  B. Ladanyi,et al.  An investigation of water dynamics in binary mixtures of water and dimethyl sulfoxide. , 2008, Journal of Physical Chemistry B.

[23]  Alexander D. MacKerell,et al.  Additive and Classical Drude Polarizable Force Fields for Linear and Cyclic Ethers. , 2007, Journal of chemical theory and computation.

[24]  M. Parrinello,et al.  Canonical sampling through velocity rescaling. , 2007, The Journal of chemical physics.

[25]  N. Yui,et al.  Molecular mobility of interlocked structures exploiting new functions of advanced biomaterials. , 2006, Chemistry.

[26]  Bao-hang Han,et al.  Cyclodextrin rotaxanes and polyrotaxanes. , 2006, Chemical reviews.

[27]  T. Takata.  Polyrotaxane and Polyrotaxane Network: Supramolecular Architectures Based on the Concept of Dynamic Covalent Bond Chemistry , 2006 .

[28]  Gerrit Groenhof,et al.  GROMACS: Fast, flexible, and free , 2005, J. Comput. Chem..

[29]  Feihe Huang,et al.  Polypseudorotaxanes and polyrotaxanes , 2005 .

[30]  S. Okabe,et al.  Sliding mode of cyclodextrin in polyrotaxane and slide-ring gel , 2005 .

[31]  J. Colmenero,et al.  Neutron Spin Echo in Polymer Systems, Chapter 1 , 2005 .

[32]  H. Beckham,et al.  Direct Synthesis of Cyclodextrin-Rotaxanated Poly(ethylene glycol)s and Their Self-Diffusion Behavior in Dilute Solution , 2003 .

[33]  N. Yui,et al.  Supramolecular design for multivalent interaction: maltose mobility along polyrotaxane enhanced binding with concanavalin A. , 2003, Journal of the American Chemical Society.

[34]  Berk Hess,et al.  GROMACS 3.0: a package for molecular simulation and trajectory analysis , 2001 .

[35]  A. Arbe,et al.  Origin of Internal Viscosity Effects in Flexible Polymers: A Comparative Neutron Spin-Echo and Light Scattering Study on Poly(dimethylsiloxane) and Polyisobutylene , 2001 .

[36]  J. F. Stoddart,et al.  Interlocked Macromolecules. , 1999, Chemical reviews.

[37]  N. Nakashima,et al.  A Light-Driven Molecular Shuttle Based on a Rotaxane , 1997 .

[38]  D. Richter,et al.  Neutron Spin Echo Investigations on the Segmental Dynamics of Polymers in Melts, Networks and Solutions , 1997 .

[39]  K Schulten,et al.  VMD: visual molecular dynamics. , 1996, Journal of molecular graphics.

[40]  H. Gibson,et al.  Rotaxanes, catenanes, polyrotaxanes, polycatenanes and related materials , 1994 .

[41]  A. Harada,et al.  Preparation and properties of inclusion complexes of polyethylene glycol with .alpha.-cyclodextrin , 1993 .

[42]  T. Darden,et al.  Particle mesh Ewald: An N⋅log(N) method for Ewald sums in large systems , 1993 .

[43]  Akira Harada,et al.  The molecular necklace: a rotaxane containing many threaded α-cyclodextrins , 1992, Nature.

[44]  J Fraser Stoddart,et al.  A molecular shuttle. , 1991, Journal of the American Chemical Society.

[45]  J. Nitsche,et al.  Window effects in zeolite diffusion and Brownian motion over potential barriers , 1991 .

[46]  D. Weaver.  Note on the interpretation of lateral diffusion coefficients. , 1982, Biophysical journal.

[47]  D. Davies,et al.  Density, refractive index, viscosity and 1H nuclear magnetic resonance measurements of dimethyl sulphoxide at 2 °C intervals in the range 20–60 °C. Structural implications , 1982 .

[48]  M. Parrinello,et al.  Polymorphic transitions in single crystals: A new molecular dynamics method , 1981 .

[49]  E. d'Agliano,et al.  Diffusion coefficient for a Brownian particle in a periodic field of force , 1978 .

[50]  Ian Thomas. Harrison,et al.  Synthesis of a stable complex of a macrocycle and a threaded chain , 1967 .

[51]  J. L. Jackson,et al.  On the Self‐Diffusion of Ions in a Polyelectrolyte Solution , 1962 .

[52]  E. Andrade,et al.  LVIII. A theory of the viscosity of liquids.—Part II , 1934 .