Molecular Thermodynamics of Polymer Chains Confined between Planar Surfaces Bearing End-Tethered Flexible Molecules
01 Jan 2012-Journal of Macromolecular Science, Part B (Taylor & Francis Group)-Vol. 51, Iss: 1, pp 164-183
TL;DR: In this article, a lattice-based model of the confinement of homopolymer free chains between two flat solid surfaces, each covered with end-tethered flexible chains, is developed.
Abstract: A lattice-based model of the confinement of homopolymer free chains between two flat solid surfaces, each covered with end-tethered flexible chains, is developed. The free energy and free energy change for the formation of the confined state from reference states of the different components are calculated based on lattice and scaling theory concepts. Entropic and energetic factors determine the free energy of the system. The dependency of free energy and free energy change on the chain lengths (molecular weights) of free polymers and tethered polymers, the density of end-tethered chains on the surfaces, the distance between the surfaces, and the various intersegment interaction energy parameters for various component species, were studied. The phase diagrams obtained in this work provide ways for designing thermodynamically stable systems in various regimes. The results are qualitatively in agreement with those from earlier models based on self-consistent field theory and experiments.
Citations
More filters
[...]
01 Mar 2000
TL;DR: In this paper, a simulation of the flow of a symmetric diblock copolymer from a bulk melt into a slit whose surfaces are modified by grafted surfactant chains, and whose walls are maintained at a constant pressure to permit the slit to open as polymer intercalates, is presented.
Abstract: Polymer-layered silicate nanocomposites may be formed by annealing layered silicate particles with a polymer melt. Polymer molecules flow from a bulk melt into the galleries between silicate sheets, swelling the silicate structure. The use of an amphiphilic intercalant raises possibilities of forming novel structures and enhancing the intercalation kinetics relative to the case of homopolymer intercalants. We perform molecular dynamics simulations of the flow of a symmetric diblock copolymer from a bulk melt into a slit whose surfaces are modified by grafted surfactant chains, and whose walls are maintained at a constant pressure to permit the slit to open as polymer intercalates. Intercalation kinetics are examined for a variety of polymer–surface and interblock interactions and for thermodynamic states in which the bulk polymer occupies either a lamellar or disordered phase. Comparison to previous simulations of homopolymer intercalation demonstrates that diblock copolymers may be used to intercalate a block that would not spontaneously intercalate as a homopolymer.
33 citations
[...]
TL;DR: In this article, a molecular model for the free energy of a confined system of diblock copolymer chains within a 2D slit with the interior surfaces having end-tethered chains is presented, based on a combined lattice and scaling theory approach.
Abstract: A molecular model for the free energy of a confined system of diblock copolymer chains within a 2D slit with the interior surfaces having end-tethered chains is presented, based on a combined lattice and scaling theory approach. The thermodynamics of a model system, based on a constrained minimization of free energy, is explored as a function of the intermolecular energy parameters for interaction between the segments of block copolymer chains, end-tethered chains, and the surfaces. The effects of chain length and the block length ratio are investigated over a wide range of values. The results obtained are qualitative in nature; however, the model can be implemented to real systems provided appropriate parameterization of the model parameters to real systems can be performed. The phase diagrams obtained here provide ways for designing thermodynamically stable systems within the physical parametric variable space.
1 citations
Cites background or methods from "Molecular Thermodynamics of Polymer..."
[...]
[...]
[...]
[...]
References
More filters
Book•
[...]
01 Jan 1995
TL;DR: In this paper, Free-Radical Chain-Growth Polymerization (FRCG) and Ionic chain-growth polymers (Ionic chain growth polymers) are discussed.
Abstract: Physical Properties and Physical Chemistry of Polymers.- Free-Radical Chain-Growth Polymerization.- Ionic Chain-Growth Polymerization.- Ring-Opening Polymerizations.- Common Chain-Growth Polymers.- Step-Growth Polymerization and Step-Growth Polymers.- Naturally Occurring Polymers.- Reactivity and Chemical Modifications of Polymers.- Polymeric Materials for Special Applications.
2,019 citations
"Molecular Thermodynamics of Polymer..." refers background in this paper
[...]
[...]
[...]
[...]
1,994 citations
"Molecular Thermodynamics of Polymer..." refers background or methods in this paper
[...]
[...]
[...]
[...]
[...]