Temperature-Dependent Conformation Behavior of Isolated Poly(3-hexylthiopene) Chains

Abstract

We use atomistic as well as coarse-grained molecular dynamics simulations to study the conformation of a single poly(3-hexylthiopene) chain as a function of temperature. We find that mainly bundle and toroid structures appear with bundles becoming more abundant for decreasing temperatures. We compare an atomistic and a Martini-based coarse-grained model which we find in very good agreement. We further illustrate how the temperature dependence of P3HT can be connected to that of simple Lennard–Jones model polymers in a vacuum. Upon adding solvent (THF) we observe the occurrence of a prominent swelling of the molecular size at a temperature of about 220 K. This swelling is in close agreement with the interpretation of recent spectroscopic experiments (Panzer et al. J Phys Chem Lett 8, 114 (2017)) which allows us to explain the experimental observations by an increased frequency of bundle structures.

Computational Approaches for Organic Semiconductors: From Chemical and Physical Understanding to Predicting New Materials

“…Owing to the lower computational cost of CG approaches, many works have leveraged these methods for accelerated modeling of OSC morphology (refs , , , and − ), donor/acceptor/solvent miscibility and blend ratio (refs , − , − ,, , , , and ), phase transitions and solvent evaporation (refs , , , − , − , and − ), diffusion, ,,, and mechanical properties. , In a series of 2010–2014 works, Lee et al developed and applied CG models for P3HT:PC 61 BM mixtures, , PBTTT:PC 61 BM, and MEH-PPV. ,,, Based on these models, they characterized a wide range of properties, including the average domain sizes, interface-to-volume ratios, and percolation ratios of P3HT:PC 61 BM blends at different weight ratios; BHJ morphologies, chain conformations, and π–π stacking; ,− , and phase transitions and solubility. ,, Likewise, in a series of recent publications that focused on the P3HT:PC 61 BM system, Munshi et al explored the morphological ramifications of preheating and annealing, P3HT molecular weight, blend ratio, and polydispersity. ,, …”

Approaches and Perspective of Coarse-Grained Modeling and Simulation for Polymer–Nanoparticle Hybrid Systems

“…MARTINI CG parameters (bonded and nonbonded) for polymers typically are constructed by matching bond and angle distributions obtained from reference all-atom simulations, the free energy of transfer of the target repeating units in organic and aqueous phases, and long-range structural properties such as radii of gyration. ,, Apart from that, polymer melt density profile, structure factor, end-to-end distance, and persistence length can also be used as the validation target. Currently, the MARTINI CG parameters are available for >50 types of polymers ranging from simple linear and branched polymers to conjugate polymers such as poly­(3-hexylthiophene) and block copolymers. ,,,,− More recently, it has been successfully used to simulate a variety of organic–inorganic systems such as block copolymers assembly, organic–electronic materials, , ionic liquids, ion-conducting materials, − polymer nanocomposites, self-assembled supramolecular materials, , and many others. , In the past decade, the MARTINI models have also been used for more complex polymer–nanoparticle systems such as graphene, carbon nanotubes, gold, and montmorillonite clay nanoparticle–polymer composites and polymers near graphite and silica surfaces. There are various studies that involve the interaction of these nanoparticles with biomolecules and polymers conducted using the MARTINI CG parameters, of which a few studies related to PNCs and polymer-tethered nanoparticles are discussed here.…”

Molecular Dynamics Analysis of Silica/PMMA Interface Shear Behavior

“…Nano-imprint lithography (NIL) allows the production of repeatable nano-scale patterns, and the injection of polymers in polycrystalline substrates. The relation between the molecular chain length and the mold cavity geometry was investigated in [30][31][32][33][34], to optimize pattern transfer. Inspired by these previous studies, we compare smooth and rough PMMA/silica interfaces, in which rough interfaces contain a notch of the order of 25 nano-meters in width and Molecular Dynamics (MD) models have shed light on the mechanical behavior of numerous polymers and composite materials used to solve multi-physics problems [7][8][9][10][11][12][13][14].…”