Radius of Gyration of Polymer Chains

1962 ◽  
Vol 36 (2) ◽  
pp. 306-310 ◽  
Author(s):  
Marshall Fixman
Keyword(s):  
Polymer Chains ◽  
Radius Of Gyration

Structure of Polymer Chains Confined in Vycor

1996 ◽  
Vol 464 ◽  
Author(s):  
Jyotsana Lal ◽  
Sunil K. Sinha ◽  
Loic Auvray
Keyword(s):  
Porous Medium ◽  
Porous Media ◽  
Form Factor ◽  
Small Angle Neutron Scattering ◽  
Pore Diameter ◽  
Polymer Chains ◽  
Bulk Solution ◽  
Radius Of Gyration ◽  
Single Chain ◽  
Molecular Weights

ABSTRACTWe observe by Small Angle Neutron Scattering (SANS) the structure of polystyrene chains in semi-dilute solutions confined in model porous medium, Vycor. The size of the free polymer chains in solution is always larger than the pore diameter, 70 Å. The use of a suitable mixture of hydrogenated and deuterated solvents and polymers enables us to directly measure the form factor of one single chain among the others. The penetration of the chain in the porous media is almost complete for the concentration (Φ = 20%) and the range of molecular weights (35000 <M< 800000) used. The measured radius of gyration of confined chains is always smaller than the radius of gyration of free chains in the equivalent bulk solution.

Calculation of the mean-square radius of gyration for polymer chains with side-groups

1992 ◽  
Vol 28 (11) ◽  
pp. 1339-1343 ◽  
Author(s):  
Zhou Zhiping ◽  
Xu Jianmin ◽  
Song Xubing ◽  
Yan Deyue
Keyword(s):  
Polymer Chains ◽  
Radius Of Gyration ◽  
Mean Square ◽  
The Mean

Collapse of Isolated Chains in a Network

1994 ◽  
Vol 376 ◽  
Author(s):  
R. M. Briber ◽  
X. Liu ◽  
B.J. Bauer
Keyword(s):  
Crosslink Density ◽  
Virial Coefficient ◽  
Linear Chain ◽  
Second Virial Coefficient ◽  
Polymer Chains ◽  
Network Density ◽  
Radius Of Gyration ◽  
Single Chain ◽  
Polystyrene Matrix ◽  
Wide Range

ABSTRACTIn this study we use small angle neutron scattering to investigate the conformation of linear deuterated polystyrene chains trapped in a crosslinked protonated polystyrene matrix. The second virial coefficient was obtained as a function of crosslink density for a wide range of crosslink density. It is shown that the second virial coefficient decreases with increasing crosslink density. By extrapolating the scattering to zero concentration of the linear chain at all values of q, the single chain scattering was obtained and radius of gyration was measured the function of network density. It was found that when the network density is low (NI < Nc where NI and Nc are the number of monomer units in the linear chain and the monomer units between crosslinks, respectively) the radius of gyration does not change. As the network density increases (NI > Nc ) radius of gyration decreases. In this region the inverse of the radius of gyration varies linearly with the inverse of Nc. When the crosslink density is very high (NI » Nc ), segregation of linear polymer chains occurs. These results are in agreement with prediction and computer simulation results of polymer chain conformation in a field of random obstacles where the crosslink junctions act as the effective obstacles.

The Effect of Tacticity and Side Chain Structure on the Coil Dimensions of Polyolefins

2018 ◽  
Author(s):  
Mohammad Atif Faiz Afzal ◽  
Jarod M. Younker ◽  
George Rodriguez
Keyword(s):  
High Throughput Screening ◽  
Waste Water Treatment ◽  
Chain Structure ◽  
Polymer Chains ◽  
Side Chain ◽  
Radius Of Gyration ◽  
Structure Property ◽  
Engine Oils ◽  
Structure Property Relationships ◽  
Dynamics Simulations

<pre>The key to the discovery of materials with targeted properties lies in the understanding of structure-property relationships. In this work, we evaluate the relationship between the polymer structure and their coil dimensions, and explore new polymers based on these relations. Coil dimensions are important features of polymers which affect their performance in various applications, including drug delivery, waste-water treatment, and engine oils. Coil dimensions of the polyolefins are dependent on the number, size, and stereo orientation of side chains along the backbone. Thus, controlling these attributes allows us to tailor the coil dimensions of polyolefins. In the proposed scheme, we calculate the radius of gyration (<i>R<sub>g</sub></i>) of polyolefin chains using molecular dynamics simulations and validate against experimental results. Simulated annealing is implemented to ensure the capture of different configurations. This model affords the ability to quantify the effect tacticity has on the coil dimensions of polyolefins. The results show the suppression of tacticity effects when the polymer chains transition to bottlebrush structures, demonstrating that the side chain steric hindrance plays an important role in the rigidity of the chain backbone. Further, the model is used to evaluate the compositional effects by determining the rigidity of propylene and 1-hexene copolymers. Combining our model with virtual high-throughput screening techniques, we evaluated the coiling behavior of hundreds of new polymers. Using the screening results, we established correlations between the structure of the side chain and the coil dimensions of polymers.</pre><pre>The supplementary material accompanying this paper includes the library of 275 polymers and their corresponding <i>K<sub>s</sub></i> values.<br></pre>

scholarly journals The Effect of Grafting Density on the Crystallization Behaviors of Polymer Chains Grafted onto One-Dimensional Nanorod

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Tongfan Hao ◽  
Yongqiang Ming ◽  
Shuihua Zhang ◽  
Ding Xu ◽  
Zhiping Zhou ◽  
...  
Keyword(s):  
Polymer Nanocomposites ◽  
Polymer Chains ◽  
Radius Of Gyration ◽  
Mean Square ◽  
Crystalline Morphology ◽  
One Dimensional ◽  
Crystallization Behaviors ◽  
Grafting Density ◽  
Dynamic Monte Carlo ◽  
The Mean

The crystallization behaviors of five polymer chain systems grafted on a nanorod and the corresponding effect of grafting density were investigated by dynamic Monte Carlo simulations. The segment density near the interfacial regions, the number of crystallites, and the mean square radius of gyration (<Rg2>) increase with increasing grafting density, which are beneficial to the enhancement of crystallizability. Meanwhile, the crystalline morphology is greatly influenced by grafting density and polymer-nanorod interaction. For the grafted system with 52 chains, a nanohybrid shish-kebab (NHSK) structure is formed, when the polymer-nanorod interaction (Eb/Ec) is -0.4. For the system with 128 chains, a NHSK structure is formed, when Eb/Ec is -1.0. For the system with 252 chains, NHSK structure cannot be formed. The findings in this work can supply important theoretical reference for the design, preparation, and application of polymer nanocomposites.

scholarly journals Coarse-Grained Simulations of the Effects of Chain Length, Solvent Quality, and Chemical Defects on the Solution-Phase Morphology of MEH-PPV Conjugated Polymers

2012 ◽  
Vol 65 (5) ◽  
pp. 463 ◽  
Author(s):  
Ming Chiu ◽  
Tak W. Kee ◽  
David M. Huang
Keyword(s):  
Polymer Chains ◽  
Coarse Grained ◽  
Radius Of Gyration ◽  
Implicit Solvent ◽  
Coarse Grained Model ◽  
Solvent Quality ◽  
Defect Content ◽  
Coarse Grained Simulations ◽  
Chain Lengths ◽  
Poor Solvent

A mesoscale coarse-grained model of the conjugated polymer poly(2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV) in implicit solvent is developed. The model is parametrized to reproduce the local structure and dynamics of an atomistic simulation model and accounts for the effects of solvent quality and saturation chemical defects on the polymer structure. Polymers with defect concentrations of 0 to 10 % are simulated using Langevin dynamics in tetrahydrofuran (THF) and in a model poor solvent for chain lengths and solution concentrations used experimentally. The polymer chains are extended in THF and collapse into compact structures in the poor solvent. The radius of gyration decreases with defect content in THF and agrees quantitatively with experiment. The structures formed in poor solvent by chains with 300 monomer units change from toroidal to cylindrical with increasing defect content, while chains containing 1000 monomers form cylinders regardless of defect content. These results have implications for energy transfer in MEH-PPV.

Meso-scale Simulations of Poly(N-isopropylacrylamide) Grafted Architectures

2014 ◽  
Vol 1619 ◽  
Author(s):  
Sanket A. Deshmukh ◽  
Ganesh Kamath ◽  
Derrick C. Mancini ◽  
Subramanian K.R.S. Sankaranarayanan ◽  
Wei Jiang
Keyword(s):  
Conformational Dynamics ◽  
Md Simulations ◽  
Polymer Chains ◽  
Effect Of Temperature ◽  
Solution Temperature ◽  
Radius Of Gyration ◽  
Core Particle ◽  
Thermosensitive Polymer ◽  
Critical Solution Temperature ◽  
Different Diameters

ABSTRACTPoly(N-isopropylacrylamide) (PNIPAM) is a thermosensitive polymer that is well-known for its behavior at a lower critical solution temperature (LCST) around 305 K. Below the LCST, PNIPAM is soluble in water, and above this temperature, polymer chains collapse and transform into a globule state. The conformational dynamics of single chains of polymer in a solution is known to be different from those of grafted structures that comprise of an ensemble of such single chains. In this study, we have carried out MD simulations of a mesoscopic nanostructure of PNIPAM polymer chains consisting of 60 monomer units grafted onto gold nanoparticles of different diameters, to study the effect of temperature and core particle size on the polymer conformations. Additionally, we have also studied the effect of grafting density on the coil-to-globule transition exhibited by PNIPAM through the LCST. The systems investigated consisted of ∼3 and ∼6 million atoms. Simulations were carried out below and above the LCST of PNIPAM, at 275K and 325K. Simulation trajectories were analyzed for radius of gyration of PNIPAM chains.

Corrigendum to: Coarse-Grained Simulations of the Effects of Chain Length, Solvent Quality, and Chemical Defects on the Solution-Phase Morphology of MEH-PPV Conjugated Polymers

2013 ◽  
Vol 66 (4) ◽  
pp. 505
Author(s):  
Ming Chiu ◽  
Tak W. Kee ◽  
David M. Huang
Keyword(s):  
Polymer Chains ◽  
Coarse Grained ◽  
Radius Of Gyration ◽  
Implicit Solvent ◽  
Coarse Grained Model ◽  
Solvent Quality ◽  
Defect Content ◽  
Coarse Grained Simulations ◽  
Chain Lengths ◽  
Poor Solvent

A mesoscale coarse-grained model of the conjugated polymer poly(2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV) in implicit solvent is developed. The model is parametrized to reproduce the local structure and dynamics of an atomistic simulation model and accounts for the effects of solvent quality and saturation chemical defects on the polymer structure. Polymers with defect concentrations of 0 to 10 % are simulated using Langevin dynamics in tetrahydrofuran (THF) and in a model poor solvent for chain lengths and solution concentrations used experimentally. The polymer chains are extended in THF and collapse into compact structures in the poor solvent. The radius of gyration decreases with defect content in THF and agrees quantitatively with experiment. The structures formed in poor solvent by chains with 300 monomer units change from toroidal to cylindrical with increasing defect content, while chains containing 1000 monomers form cylinders regardless of defect content. These results have implications for energy transfer in MEH-PPV.

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