Phase transitions in block copolymers resulting in a discontinuous change of the spatial period of mesophases

Abstract

The phase behavior of a melt of two-scale multiblock copolymers has been theoretically studied in the framework of the Weak Segregation Limit theory with a twocomponent order parameter. The existence of a thermodynamically stable mesophase with two scales of the space periodicity has been revealed for a melt of monodisperse nonperiodic heteropolymers. For the first time a discontinuous change with temperature of the spatial period of the mesophases has been predicted.

Perpendicular lamellar-in-lamellar and other planar morphologies in A-b-(B-b-A)2-b-C and (B-b-A)2-b-C ternary multiblock copolymer melts

“…To speed up the iteration procedure convergence, after a certain number of Picard iterations (17) one should switch to the iteration method by Ng, which is characterized by a faster convergence. The details of the Ng method are described in Refs.…”

“…This phenomenon became an attractive area of research both experimentally [1][2][3][4][5][6][7][8][9][10][11][12] and theoretically, [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] during the last decades. First, the two-length-scale structures, which might be called lamellar-in-lamellar structures (see Fig.…”

“…Several other examples of hierarchical structures can be found in Refs. 9-13. The morphologies occurring in multiblock copolymers with various architectures and interaction parameters were studied theoretically both within the weak [14][15][16][17] and strong segregation approach (SSA) [18][19][20][21] as well as within the framework of the self-consistent field theory (SCFT). [22][23][24][25][26][27][28][29] In particular, the transitions between the parallel lamellar-in-lamellar structures L || (n) with different numbers n of thin layers per large period were studied via the SSA [18][19][20] and SCFT.…”

New Results in Weak Segregation Limit Theory of Block Copolymers

“…[27] Later a diagram algorithm was suggested [28] enabling one to write down analogous expressions for any mesophases with two scales of spatial periodicity. Using this algorithm to consider a melt of two-scale macromolecules the authors of paper [29] managed to reveal for the first time the possibility of the existence on the phase diagram of a region of thermodynamic stability of some two-scale mesophase.…”

Lamellar-in-lamellar structure of binary linear multiblock copolymers

“…They became an attractive subject for experimental [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] and theoretical [16][17][18][19][20] investigations due to the possibilities to form structures combining different periodicities. One of the first observations of a doubleperiodic self-assembled structure involved the self-assembly in polystyrene-block-poly͑4-vinylpyridine͒ ͑PS-b-P4VP͒ diblock copolymers with hydrogen-bonded pentadecylphenol ͑PDP͒ side chains to the P4VP block.…”