Structure and phase behaviour of diblock copolymer monolayers investigated by means of Monte Carlo simulation

Block copolymers for supercapacitors, dielectric capacitors and batteries

Block copolymer-based energy storage emerges as an active interdisciplinary research field. This topical review presents a survey of the recent advances in block copolymers for energy storage. In the first section, we introduce the background of electrochemical energy storage and block copolymer thermodynamics. In the second section, we discuss the current understandings of block copolymer chemistry, processing, pore size, and ionic conductivity. In the third section, we summarize the design principles and state-of-the-art applications of block copolymers in three energy storage devices, namely, supercapacitors, dielectric capacitors, and batteries. Lastly, we present our perspectives on future possible breakthroughs and associated challenges that are essential to propel the development of advanced block copolymers for energy storage. We expect the review to encourage innovative studies on integrating block copolymers into energy storage applications.

Microscopic density functional theory for monolayers of diblock copolymers

We propose density functional theory for diblock copolymers in two dimensions. Our theoretical framework is based on Wertheim's first order thermodynamic perturbation theory. Using the proposed approach, we investigate the structure and phase behavior of monolayers of symmetric diblock copolymers. We find that the phase behavior of symmetric diblock copolymer monolayers is similar to that in 3D. This includes the scaling of the equilibrium lamellar width with chain length. We find that the topology of the resulting phase diagrams depends on the chain length and the unlike segment interaction incompatibility and involves either one, two, or three triple points (one of them being the peritectic point). We expect that a similar phase behavior could be obtained for monolayers of colloidal suspensions with carefully tuned interparticle interactions.

Density functional theory for polymeric systems in 2D

We propose density functional theory for polymeric fluids in two dimensions. The approach is based on Wertheim's first order thermodynamic perturbation theory (TPT) and closely follows density functional theory for polymers proposed by Yu and Wu (2002 J. Chem. Phys. 117 2368). As a simple application we evaluate the density profiles of tangent hard-disk polymers at hard walls. The theoretical predictions are compared against the results of the Monte Carlo simulations. We find that for short chain lengths the theoretical density profiles are in an excellent agreement with the Monte Carlo data. The agreement is less satisfactory for longer chains. The performance of the theory can be improved by recasting the approach using the self-consistent field theory formalism. When the self-avoiding chain statistics is used, the theory yields a marked improvement in the low density limit. Further improvements for long chains could be reached by going beyond the first order of TPT.