The ordering of symmetric diblock copolymers: A comparison of self-consistent-field and density functional approaches

Abstract

Articles you may be interested inOn the comparisons between dissipative particle dynamics simulations and self-consistent field calculations of diblock copolymer microphase separation Effects of interaction range and compressibility on the microphase separation of diblock copolymers: Mean-field analysis Polymer reference interaction site model ͑PRISM͒ based density functional ͑DF͒ theory is used to evaluate the structure and thermodynamics of structurally symmetric, freely jointed, diblock chains with 0.50 volume fraction. These results are compared to the results of self-consistent-field ͑SCF͒ theory. Agreement between the predictions of the SCF and DF theories is found for the lamella spacing well above the order-disorder transition ͑ODT͒ and for the qualitative behavior of the interfacial thickness as a function of both chain length and Flory-Huggins parameter. Disagreement is found for the magnitude of the interfacial thickness where DF theory indicates that the thickness is 1.7Ϯ0.2 times larger than that predicted by SCF theory. It appears that behavior on the monomer length scale is sensitive to system specific details which are neglected by SCF theory.

Revisited Block Copolymer/Nanoparticle Composites: Extension of Interfacial Statistical Associating Fluid Theory

“…It is worthwhile to point out the average packing fraction (0.3) in this study is quite low and compressibility effect might be an important factor, which is neglected in the FH theory. Note that the power indices of the chain length dependence from iSAFT predictions are relatively closer to the value of −0.9 reported by Nath et al, who employed a PRISM-based DFT and dealt with a denser system with bulk packing fraction of 0.524.…”

“…In this work, we extend iSAFT toward quantitative accuracy in the prediction of both ODT temperature and molecular structure. The extensions of the theory are tested and compared with simulation and theories ,,− first in simpler pure BCP melts and then BCP/NP composites. To our best knowledge, this work will be the first one to study the order–disorder transition with a TPT1-based theory.…”

Structure and assembly of dense solutions and melts of single tethered nanoparticles

“…25,26 Of course, simulations have the powerful advantage of being able to predict and visualize ordered phases in contrast to homogeneous phase PRISM theory, which describes only a generic tendency for microphase separation. This limitation can potentially be relaxed by combining liquid state structural information with thermodynamic density functional methods, 25,27 a topic that is beyond the scope of this study.…”

Symmetric diblock copolymers in thin films. II. Comparison of profiles between self-consistent field calculations and Monte Carlo simulations

“…Density functional or P-RISM calculations of more realistic models might account for the changes in the local fluid structure. Comparing self-consistent field calculations in the framework of the Gaussian chain model and density functional theory for a model with local fluid structure, Nath and co-workers [15,16] observed rather pronounced deviations between both approaches. (v) The confining surfaces create a sharp density gradient.…”