scholarly journals Impact of the Solvent Quality on the Local Dynamics of Soft and Swollen Polymer Nanoparticles Functionalized with Polymer Chains

2020 ◽  
Vol 53 (17) ◽  
pp. 7561-7569
Author(s):  
Young-Gon Kim ◽  
Héloïse Thérien-Aubin
Keyword(s):  
Polymer Chains ◽  
Polymer Nanoparticles ◽  
Local Dynamics ◽  
Solvent Quality

Shear Forces between Tethered Polymer Chains as a Function of Compression, Sliding Velocity, and Solvent Quality

2003 ◽  
Vol 36 (2) ◽  
pp. 389-398 ◽  
Author(s):  
Phillip A. Schorr ◽  
Thomas C. B. Kwan ◽  
S. Michael Kilbey ◽  
Eric S. G. Shaqfeh ◽  
Matthew Tirrell
Keyword(s):  
Polymer Chains ◽  
Sliding Velocity ◽  
Shear Forces ◽  
Solvent Quality ◽  
Tethered Polymer Chains

Neutron Reflection Studies of Swelling of Chemically End-Grafted Polymer Chains

1994 ◽  
Vol 376 ◽  
Author(s):  
Alamgir Karim ◽  
S.K. Satija ◽  
P. Gallagher ◽  
J.F. Douglas ◽  
L.J. Fetters
Keyword(s):  
Polymer Networks ◽  
The Body ◽  
Polymer Chains ◽  
Cross Linking ◽  
Neutron Reflection ◽  
Grafted Polymer ◽  
Solvent Quality ◽  
Grafting Density ◽  
Fluctuation Effects ◽  
Theta Solvent

ABSTRACTNeutron reflection is used to compare the swelling of two chemically end-grafted polystyrene brushes having different grafting densities exposed to a theta solvent cyclohexane and to a good solvent toluene. The relative swelling of tie brushes with a variation of solvent quality becomes smaller and the temperature dependence becomes weaker with an increase of grafting density. This type of swelling is very similar to polymer networks where an increase of cross-linking density leads to a decreased range of swelling and diminished dependence of the swelling. Our model density profile fits to the body of both brushes is parabolic in a good solvent so that some fluctuation effects, as found generally in lower density brushes, are obtained as the brush expands.

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.

Crosslinked polymer nanoparticles containing single conjugated polymer chains

2017 ◽  
Vol 5 (2) ◽  
pp. 024001 ◽  
Author(s):  
Rodrigo A Ponzio ◽  
Yésica L Marcato ◽  
María L Gómez ◽  
Carolina V Waiman ◽  
Carlos A Chesta ◽  
...  
Keyword(s):  
Conjugated Polymer ◽  
Polymer Chains ◽  
Polymer Nanoparticles ◽  
Crosslinked Polymer ◽  
Conjugated Polymer Chains

Pressure-Sensitive Microvalves Made from Polymer Brushes

1994 ◽  
Vol 360 ◽  
Author(s):  
E.M. Sevick ◽  
D.R.M. Williams
Keyword(s):  
Polymer Brushes ◽  
Critical Pressure ◽  
Feedback Mechanism ◽  
Polymer Chains ◽  
Narrow Slit ◽  
Solvent Quality ◽  
Pressure Sensitive ◽  
Wide Range ◽  
Valve Assembly ◽  
Valve Operation

AbstractWe describe a novel microvalve, constructed from polymer chains end-grafted onto opposing surfaces of a narrow slit. The assembly of polymer chains acts as both sensor and valve for microflow control and bypasses the need to construct an external feedback mechanism. This microflow control results from densely grafted chains which repel one another and stretch away from the surface, forming a brush which acts as an elastic and impenetrable layer. The height of a sheared brush increases or decreases depending upon solvent quality, i.e the layer can show a negative Poission's ratio. The discharge through the brushlined conduit is a non-linear function of pressure enabling different modes of valve operation. For brushes which extend moderately into the inter-slit region the valve assembly maintains constant discharge over a wide range of pressure. For brushes which extend far into the inter-slit region the valve assembly cuts off flow above a critical pressure, limiting the maximum discharge.

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