Effect of surface field on the morphology of a symmetric diblock copolymer under cylindrical confinement

Abstract

We have used lattice Monte Carlo simulations to investigate the molecular assembly of symmetric diblock copolymer melts within cylindrical nanochannels. We studied the effect that the surface field has on the copolymer morphology in three cylinders having different diameters. Upon varying the strength of the surface field, we observed a variety of morphologies, including stacked-disk, single-helix, catenoid-cylinder, gyroidal, stacked-circle, and concentric cylindrical barrel structures. The results of these simulations should be helpful when designing polymeric nanomaterials confined in cylindrical nanochannels.

Gyroid-Forming Diblock Copolymers Confined in Cylindrical Geometry: A Case of Extreme Makeover for Domain Morphology

“…In this case, the wall of the confining pore is strongly attractive to the majority The one-ring lamella is similar to that observed for symmetric DBCPs when confined in selective pores [16][17][18][19][20][21][22][23][24][25].…”

“…The morphologies shown in Figure 3 can be compared with those obtained from the cylinder-or lamella-forming DBCPs under the cylindrical confinement [16][17][18][19][20][21][22][23][24][25][26][27][28]. We notice that helices and stacked toroids, frequently observed in the cylinder-forming system inside majority-selective pores, never occur in the gyroid-forming systems.…”

“…Therefore, it is necessary to explore the phase diagram in three-dimensional space. In the last few years, many novel structures, such as porous lamella (mesh) structures, lamellae parallel to the pore axis (parallel lamellae), and helices, were predicted using computer simulations for lamella-forming DBCPs confined in nanopores [19][20][21][22][23][24][25]. For cylinder-forming DBCPs, it has been shown by simulations [23][24][25][26] and SCFT calculations [27,28] that novel structures such as helices and stacked toroids spontaneously form inside the cylindrical pore.…”

Surface-field-induced microstructures of asymmetric diblock copolymer nanoparticles

“…A large number of studies have contributed to the confinement-induced effects on the microstructures of diblock copolymers confined in thin films and cylindrical nanopores. [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] The results of these studies indicate that cylindrical nanopores engender distinct confinement-induced effects on the microstructures compared with those of thin films because of the different symmetries of their confinement surfaces. When the polymer chains are confined in a spherical environment provided by the nanoparticle boundaries, they may show unique characteristics.…”

“…This adsorption interaction is similar to that commonly used in MC simulations, which provides a convenient way to compare the present results with those from the available MC simulations. 8,9,12,22 In the logarithmic term, the singlechain partition function, Q, can be expressed as Q ¼ R q r; 1 ð Þdr in the mean fields o A(B) . The segment distribution function, q(r, s), is the statistical weight of a chain segment of contour length s containing a free-chain end with its connected end located at r. The function q(r, s) satisfies the modified diffusion equation in the mean fields; that is,…”