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Main Research Topics in Our Group:

 

Polymer Dynamics and Glass Transition 

 

 

  Dynamics and Functions of Biological Macromolecules  

 

 

      Nano-structured  and  Nano-composite  Materials       

 

Nano-Photonics, Plasmonics

 

 

 

 

 

 

 

 

 

 

 

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Polymer Dynamics and Glass Transition

      

    We study Polymer Dynamics, Dynamics of Glass Forming Systems and the Glass Transition in the entire frequency range from vibrations to reptation. We use light and neutron scattering spectroscopy, and also dielectric and mechanical relaxation spectroscopy. 

 

Recent Most Important Publications:

 

L. Hong, A. B. Begen, Kisliuk, S. Pawlus, M. Paluch, A.P. Sokolov, “Influence of Pressure on Quasielastic Scattering in Glasses: Relationship to the Boson Peak”, Phys. Rev. Letters 102, 145502 (2009).

A. P. Sokolov and K. S. Schweizer, Resolving the mystery of chain friction mechanism in polymer liquids, Phys. Rev. Lett. 102, 248301 (2009).

A.L. Agapov, A.P. Sokolov, Does molecular weight dependence of Tg correlate to Me? Macromolecules 42, 2877-2878 (2009).

L. Hong, B. Begen, A. Kisliuk, C. Alba-Simionesco, V.N. Novikov, A.P. Sokolov, Influence of density (pressure) on the boson peak in polymers, PRB 78, 134201/1-11 (2008).

 

K. Kunal, C.G. Robertson, S. Pawlus, S. F. Hahn, A. P. Sokolov, Role of chemical structure in fragility of polymers: a qualitative picture, Macromolecules 41, 7232-7238 (2008).

 

L. E. Bove, C. Petrillo, A. Fontana, and A. P. Sokolov, Damping of Sound Waves in the THz range and Strength of the Boson Peak, J.Chem.Phys. 128, 184502/1-6 (2008).

 

K. Niss, B.Begen, B. Frick, J. Ollivier, A. Beraud, A. Sokolov, V. Novikov, C. Alba-Simionesco, Influence of pressure on the boson peak: Stronger than Elastic Modulus Transformation, Phys.Rev. Letters 99, 055502 (2007).

 

A.P. Sokolov, V.N. Novikov, Y. Ding, Why many Polymers are so Fragile. J.Phys.Cond.Matt. 19, 205116 (2007).

 

A.P. Sokolov, Y. Hayashi, Breakdown of Time-Temperature Superposition: From Experiment to the Coupling Model and Beyond, J.Non-Cryst.Solids 353, 3838-3844 (2007).

 

Y. Ding, A.P. Sokolov, “Breakdown of Time Temperature Superposition Principle and Universality of Chain Dynamics in Polymers”, Macromolecules 39, 3322-3326 (2006).

 

V.N. Novikov, A.P. Sokolov, Correlation of fragility and Poisson’s ratio: Difference between metallic and non-metallic glassformers, Phys.Rev.B 74, 064203-1-7 (2006).

 

V.N. Novikov, Y. Ding, A.P. Sokolov, “Correlation of fragility of supercooled liquids with elastic properties of glasses”, Phys.Rev.E 71, 061501-1-12 (2005).

 

V.N. Novikov, A.P. Sokolov, " Poisson’s ratio and fragility of glass-forming liquids ", Nature 431, 961- 963 (2004).

 

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Dynamics and Functions of Biological Macromolecules

    We study Dynamics of Proteins, RNA and DNA, mechanism of their interactions with solvent, and relationship between protein dynamics and function. We use neutron and light scattering as well as dielectric relaxation spectroscopy.

    Recent Most Important Publications:

 

J. H. Roh, R. M. Briber, A. Damjanovic, D. Thirumalai, S. A. Woodson, A. P. Sokolov, Dynamics of tRNA at Different Levels of Hydration. Biophys.J. 96, 2755-2762 (2009).

 

S. Pawlus, S. Khodadadi and A. P. Sokolov, Conductivity in Hydrated Proteins: No Signs of the Fragile-to-Strong Crossover, Phys.Rev.Lett. 100, 108103 (2008).

 

Sheila Khodadadi, Sebastian Pawlus, Alexei Sokolov, Influence of Hydration on Protein Dynamics: Combining Dielectric and Neutron Scattering Spectroscopy Data. J. Phys. Chem. B 112, 14273 (2008).

 

S. Khodadadi, S. Pawlus, J.H. Roh, V. Garcia Sakai, E. Mamontov, A.P. Sokolov, The Origin of the Dynamic Transition in Proteins, J.Chem.Phys. 128, 195106/1-5 (2008).

 

A.P. Sokolov, J.H. Roh, E. Mamontov, V. García Sakai, Role of Hydration Water in Dynamics of Biological Macromolecules, Chem.Phys. 345, 212-218 (2008).

 

Gokhan Caliskan, Robert M. Briber, D. Thirumalai, Victoria Garcia-Sakai, Sarah A. Woodson, Alexei P. Sokolov, “Dynamic Transition in tRNA is Solvent Induced”, J.Amer.Chem.Soc. 128, 32-33 (2006).

 

J. H. Roh, J. E. Curtis, S. Azzam, V. N. Novikov, I. Peral, Z. Chowdhuri, R. B. Gregory and A. P. Sokolov, “Influence of Hydration on the Dynamics of Lysozyme”, Biophys. J. 91 2573-2588 (2006).

 

J.H. Roh, V.N. Novikov, R.B. Gregory, J.E. Curtis, Z. Chowdhuri, A.P. Sokolov, “Onsets of Anharmonicity in Protein Dynamics”, Phys.Rev.Lett. 95, 038101-1-4 (2005).

 

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Nano-structured and Nano-composite Materials

 

    We study influence of nano-fillers (CNT, fuellerens, clays and other nano-particles) on mechanical and electrical properties of polymers. We also analyze mechanical properties of nano-structured materials, role of confinement in dynamic and thermodynamic properties. We use light scattering, dielectric and mechanical relaxation spectroscopy.

   

  Recent Most Important Publications:

 

Y. Ding, S. Pawlus, A.P. Sokolov, J.F. Douglas, A. Karim, C.L. Soles, Dielectric Spectroscopy Investigation of Relaxation in C60-Polyisoprene Nanocomposites, Macromolecules 42, 3201-3206 (2009).

 

R.D. Hartschuh, S.P. Wargacki, H. Xiong, J. Neiswinger, A. Kisliuk, S. Sihn, V. Ward, R.A. Vaia, and A.P. Sokolov, How rigid are viruses.  Phys.Rev.E 78, 021907/1-9 (2008).

 

Pang, Yi; Meador, Michael; Sokolov, Alexei; Yi, Wenhui; Lebron, Marisabel; Malkovskiy, Andrey, Wrapping of Single-Walled Carbon Nanotubes by a p-Conjugated Polymer: The Role of Polymer Conformation-Controlled Size Selectivity, J. Phys. Chem. B 112, 12263-12269 (2008).

 

T.-E. Chang, A. Kisliuk, S.M. Rhodes, W. J. Brittain, A.P. Sokolov, Conductivity and Mechanical Properties of Well-dispersed Single-wall Carbon Nanotube/Polystyrene Composite, Polymer 47, 7740-7746 (2006).

 

R. D. Hartschuh, A. Kisliuk, V. Novikov, A. P. Sokolov, P. R. Heyliger, C. M. Flannery, W. L. Johnson, C. L. Soles, W. L. Wu, “Acoustic Modes and Elastic Properties of Polymeric Nanostructures”, Appl. Phys. Letters 87, 173121-1-3 (2005).

 

T.E. Chang, L.R. Jensen, A. Kisliuk, R.B. Pipes, R. Pyrz, A.P. Sokolov, “Microscopic mechanism of reinforcement in single-wall carbon nanotube / polypropylene nanocomposite”, Polymer 46, 439-444 (2005).

 

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Nano-Photonics, Plasmonics

    We are developing scanning Nano-Raman Spectroscopy based on aperturelees near-field optics. We are also working on developments of plasmonic based substrates with extreme surface enhanced Raman signals for a possible use in highly sensitive and very selective sensors.

    Recent Most Important Publications:

 

Carlos A. Barrios, Andrey V. Malkovskiy, Alexander M. Kisliuk, Alexei P. Sokolov, Mark D. Foster, Highly Stable, Protected Plasmonic Nanostructures for Tip Enhanced Raman Spectroscopy (TERS), J. Phys. Chem. C 113, 8158-8161 (2009).

 

N. Lee, R.D. Hartschuh, D. Mehtani, A. Kisliuk, M.D. Foster, A.P. Sokolov, J.F. Maguire, M. Green, “High Contrast Scanning Nano-Raman Spectroscopy of Silicon”, J.Raman Spectr. 38, 789-796 (2007).

 

D. Mehtani, N. Lee, R. D. Hartschuh, A. Kisliuk, M.D. Foster, A. P. Sokolov, J.F. Maguire, Scanning Nano-Raman Spectroscopy of Silicon and Other Semiconducting Materials”, In: Tip Enhancement, Eds. S. Kawata and V.M. Shalaev (Elsevier, Amsterdam, 2007), pp. 177-203.

 

D Mehtani, N Lee, R D Hartschuh, A Kisliuk, M D Foster, A P Sokolov, F Čajko and I Tsukerman, “Optical properties and enhancement factors of the tips for apertureless near-field optics”, J. Optics A: Pure and Appl. Optics 8, S183-S190 (2006).

 

D. Mehtani, N. Lee, R. D. Hartschuh, A. Kisliuk, M.D. Foster, A. P. Sokolov, J. F. Maguire, Nano-Raman Spectroscopy with Side-illumination Optics, J. Raman Spectr. 36, 1068-1075 (2005).

 

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