Conformational properties of rigid-chain amphiphilic macromolecules: The phase diagram

Abstract

Conformational properties of rigid-chain amphiphilic macromolecules Markov, V. A.; Vasilevskaya, V. V.; Khalatur, P. G.; ten Brinke, G.; Khokhlov, A. R. IMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite from it. Please check the document version below. Document Version Publisher's PDF, also known as Version of record Publication date: 2008Link to publication in University of Groningen/UMCG research database Citation for published version (APA): Markov, V. A., Vasilevskaya, V. V., Khalatur, P. G., ten Brinke, G., & Khokhlov, A. R. (2008). Conformational properties of rigid-chain amphiphilic macromolecules: The phase diagram. Polymer Science. Series A, 50(6), 621-629. DOI: 10.1134/S0965545X08060059 Copyright Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. 621ISSN 0965-545X, Polymer Science, Ser. A, 2008, Vol. 50, No. 6, pp. 621-629. © Pleiades Publishing, Ltd., 2008. Original Russian Text © V.A. Markov, V.V. Vasilevskaya, P.G. Khalatur, G. ten Brinke, A.R. Khokhlov, 2008, published in Vysokomolekulyarnye Soedineniya, Ser. A, 2008 INTRODUCTIONMany synthetic and biological macromolecules are rigid-chain entities. One of the most rigid natural macromolecules is the DNA double helix. It is not surprising that rodlike macromolecules have been an object of close scientific interest over the last decades and this interest is not passing [1][2][3][4][5][6][7][8][9][10][11].A very interesting feature of rodlike macromolecules is their ability to form globules of a sophisticated shape. For example, it is known that the DNA double helix coils up into a toroidal structure in vivo, occurring in phage capsules, and in vitro during compaction in multivalent ion and surfactant solutions [12][13][14][15][16][17][18][19][20][21] of globules, of rigid-chain macromolecules is the rodlike globule in which the chain simply folds several times. Rodlike globules coexist with toroidal globules [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. In theoretical studies and computer simulations of rigid-chain macromolecules, homopolymer macromolecules with persistent and freely jointed mechanisms of flexibility have usually been considered [1][2][3][4][5][6][7][8][9][10][11].However, many macromolecules (including singlestrand DNA and proteins) are amphiphilic, that is, contain hydrophobic and hydrophilic groups in each monomer unit. The duality of units determines their simultaneous affinity for and incompatibility with both polar and nonpolar solvents. Being placed in a mixture of an organic solvent and an immiscible inorganic solvent, such macromolecules prefer to be accommodated ...

Polyelectrolyte Complexes Consisting of Macromolecules With Varied Stiffness: Computer Simulation

“…The discontinuous coil‐to‐globule transitions are also characteristic for some amphiphilic polymers42–47 involving both soluble (H) and insoluble (P) groups in their chains (either in distinct units in the case of amphiphilic copolymers or as parts of the same unit in amphiphilic homopolymers). Amphiphilic polymers with annealed HP structure (i.e., when each monomer unit can reversibly switch between H and P states) can undergo a first‐order coil‐to‐globule transition even in the case of completely flexible chains42: the density of the HP globule at the transition point remains finite in the limit of very long chains N → ∞ (the density is defined by the energy contrast between P and H states in the dilute regime).…”

Self-assembly of bis-salphen compounds: from semiflexible chains to webs of nanorings

“…1 In modern materials engineering, the formation of micro-and nano-rings by piercing of a deflating vesicle as solvent evaporates (figure 1d). 15,19 Another phenomenon leading to the formation of molecular rings is the "coil-to-toroidal globule" transition, [20][21][22][23][24] observed previously for isolated chains of "semiflexible" polymers, such as DNA, 25 xanthan 26 among others. Chains of such polymers stay rigid at the nanometre level, but are flexible at a larger scale.…”

Self-Organization in Solutions of Stiff-Chain Amphiphilic Macromolecules

“…To decrease these losses, homopolymer stiff-chain macromolecules form not spherical globules but globules of complex toroidal or rod-like form. − The amphiphilic stiff-chain macromolecules while collapsing are obliged form structures which have both minimal bend energy and “core-shell” organization. Our calculations show that depending on stiffness parameters amphiphilic macromolecules form cylindrical globules with a blob-like chain organization, collagen-like, and toroidal structures. − Hydrophobic groups in such structures occupy the inner parts, and hydrophilic ones are arranged at the surface. The total bending stress of the chain in this case is rather high because of the high stiffness of the macromolecule.…”

“…The conformational properties of macromolecules − and properties of their concentrated solutions , depend essentially on the polymeric chain stiffness. The collapse of stiff macromolecules is accompanied not only by a great reduction of the entropy of the monomeric units, but also by essential energy losses due to the bends in the polymeric chain.…”