Effect of polymer chain stiffness on initial stages of crystallization of polyetherimides: Coarse‐grained computer simulation

Abstract

We use dissipative particle dynamics simulation to study the role of the intramolecular stiffness in the crystallization process of aromatic polyetherimides. We have developed and parameterized a coarse‐grained model for polyimides R‐BAPB and R‐BAPS, which have similar chemical structures but different macroscopic properties. The former one is known as semicrystalline, while the latter one is amorphous. In our model, the only difference between these two polyimides is the intramolecular stiffness. We show that this model can reasonably reproduce the structure formation in polyimide melts. We observe initial stages of crystallization of polyimide R–BAPB while R‐BAPS stays amorphous. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017, 55, 1254–1265

Mesoscale Simulations on Morphology Design in Conjugated Polymers and Inorganic Nanoparticles Composite for Bulk Heterojunction Solar Cells

“…[91] We used simulation protocols developed by us earlier for these purposes. [92][93][94] As shown in Table 1, the accuracy of predictions of solubility parameters using semiempirical methods in most cases is in good agreement with the results obtained using the MD method.…”

“…To illustrate the extent of phase separation in the system, we calculate the order parameter which shows the degree of ordering (inhomogeneity) of the spatial distribution of beads in the simulation cell with the volume V [ 60,94 ] where is the local density of beads of the type at time t in the vicinity of the point and is the volume fraction of the component α . The values correspond to a homogeneous CP/NP mixture, whereas the values exceeding 0.1 [ 105 ] indicate the macrophase separation (separation of the mixture into two domains containing mainly CP chains and NPs, respectively) in the system.…”

“…To illustrate the extent of phase separation in the system, we calculate the order parameter Λ α which shows the degree of ordering (inhomogeneity) of the spatial distribution of beads in the simulation cell with the volume V [60,94] Λ α ðtÞ ¼ 1…”

Crystallization in melts and poor-solvent solutions of semiflexible polymers: extensive DPD study

“…Therefore, we have a solution of selfavoiding semi-flexible chains, and such a system has a tendency to undergo lyotropic nematic ordering transition 63,64 at high polymer concentrations due to steric interactions only (i.e., due to excluded volume effect), and this orientational ordering is usually the first stage of a possible crystallization transition at later stages, depending on the model. 25,32,80 The obtained average distance between linked monomer units is l = 0.48 (in units of r c ), the chain persistence length b is about 2.3 monomer units, i.e., b = b • l = 1.1 in units of r c , as we have estimated using the bond autocorrelation analysis 81,82 (for calculation of persistence length a single chain was simulated in a solvent with χ = 0.5 and the data has been averaged over 5 independent runs -to check once more!). Note, that the intramolecular stiffness is actually not large in our model, however, the additional stiffening of chains (increasing of the persistence length) takes place due to nematic ordering.…”

Coarse-Grained Molecular Dynamics Modeling of a Branched Polyetherimide

“…Several groups have applied these methods to construct coarse-grained MD models of polyimides [67][68][69][70][71][72][73] and polyetherimides. [74][75][76] Clancy et al coarse-grained polyimides based on the BPDA dianhydride and three different APB diamine isomers into chains of linked vectors and used such linked-vector chains to quickly obtain relaxed configurations of the polymers that can be reverse-mapped to atomistic systems. [67,68] Odegard et al used this technique to build all-atom configurations for the representative volume elements of the silica nanoparticle/BPDA-APB polyimide composites with various interfacial treatments.…”