Adsorption of a directed polymer subject to an elongational force

Orlandini, Enzo; Tesi, Maria Carla; Whittington, S G

doi:10.1088/0305-4470/37/5/005

Cited by 46 publications

(105 citation statements)

References 10 publications

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“…These include studies of models with intermediate phases [5,10,14,15], dependence on pulling directions [16], models with additional features like semiflexibility [17], heterogeneity [9,18,19,20,21], saturation of hydrogen bonding [22], random forcing [23] etc. A similar problem of unzipping of an adsorbed polymer from the surface has also been studied [24,25]. Experimental studies use various micro-manipulation techniques [26,27,28].…”

Section: Introductionmentioning

confidence: 99%

Can a double stranded DNA be unzipped by pulling a single strand?: Phases of adsorbed DNA

Kapri

2009

The Journal of Chemical Physics

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We study the unzipping of a double stranded DNA (dsDNA) by applying an external force on a single strand while leaving the other strand free. We find that the dsDNA can be unzipped to two single strands if the external force exceeds a critical value. We obtain the phase diagram which is found to be different from the phase diagram of unzipping by pulling both the strands in opposite directions. In the presence of an attractive surface near DNA, the phase diagram gets modified drastically and shows richer surprises including a critical end point and a triple point.

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Section: Introductionmentioning

confidence: 99%

Can a double stranded DNA be unzipped by pulling a single strand?: Phases of adsorbed DNA

Kapri

2009

The Journal of Chemical Physics

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“…In particular, directed walk models of polymers [1][2][3] played an important role in studying homopolymer adsorption [4][5][6][7][8][9][10][11][12] and collapse [13][14][15][16][17] and related problems of force-induced desorption [18][19][20][21][22][23][24][25][26] and unfolding of a collapsed macromolecule [27,28]. Random [29][30][31] and periodic [32][33][34] copolymer adsorption and mechanical desorption [35][36][37] were also studied with the aid of directed models.…”

Section: Introductionmentioning

confidence: 99%

Adsorption of symmetric random copolymer onto symmetric random surface: the annealed case

Polotsky¹

2015

Condens. Matter Phys.

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Adsorption of a symmetric (AB ) random copolymer (RC) onto a symmetric (ab ) random heterogeneous surface (RS) is studied in the annealed approximation by using a two-dimensional partially directed walk model of the polymer. We show that in the symmetric case, the expected a posteriori compositions of the RC and the RS have correct values (corresponding to their a priori probabilities) and do not change with the temperature, whereas second moments of monomers and sites distributions in the RC and RS change. This indicates that monomers and sites do not interconvert but only rearrange in order to provide better matching between them and, as a result, a stronger adsorption of the RC on the RS. However, any violation of the system symmetry shifts equilibrium towards the major component and/or more favorable contacts and leads to interconversion of monomers and sites.

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“…In a different study, 15 the dependence of the critical desorption force on temperature was investigated analytically for directed-walk models in two and three dimensions. Different classes of directed walks were considered in two dimensions, all leading to a monotonic decrease in the desorption force with increasing temperature.…”

Section: Introductionmentioning

confidence: 99%

Temperature effects in the mechanical desorption of an infinitely long lattice chain: Re-entrant phase diagrams

Skvortsov

Klushin

Fleer

et al. 2009

The Journal of Chemical Physics

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We consider the mechanical desorption of an infinitely long lattice polymer chain tethered at one end to an adsorbing surface. The external force is applied to the free end of the chain and is normal to the surface. There is a critical value of the desorption force f tr at which the chain desorbs in a first-order phase transition. We present the phase diagram for mechanical desorption with exact analytical solutions for the detachment curve: the dependence of f tr on the adsorption energy ͑at fixed temperature T͒ and on T ͑at fixed ͒. For most lattice models f tr ͑T͒ displays a maximum. This implies that at some given force the chain is adsorbed in a certain temperature window and desorbed outside it: the stretched state is re-entered at low temperature. We also discuss the energy and heat capacity as a function of T; these quantities display a jump at the transition͑s͒. We analyze short-range and long-range excluded-volume effects on the detachment curve f tr ͑T͒. For short-range effects ͑local stiffness͒, the maximum value of f tr decreases with stiffness, and the force interval where re-entrance occurs become narrower for stiffer chains. For long-range excluded-volume effects we propose a scaling f tr ϳ T 1− ͑T c − T͒ / around the critical temperature T c , where = 0.588 is the Flory exponent and Ϸ 0.5 the crossover exponent, and we estimated the amplitude. We compare our results for a model where immediate step reversals are forbidden with recent self-avoiding walk simulations. We conclude that re-entrance is the general situation for lattice models. Only for a zigzag lattice model ͑where both forward and back steps are forbidden͒ is the coexistence curve f tr ͑T͒ monotonic, so that there is no re-entrance.

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Adsorption of a directed polymer subject to an elongational force

Cited by 46 publications

References 10 publications

Can a double stranded DNA be unzipped by pulling a single strand?: Phases of adsorbed DNA

Can a double stranded DNA be unzipped by pulling a single strand?: Phases of adsorbed DNA

Adsorption of symmetric random copolymer onto symmetric random surface: the annealed case

Temperature effects in the mechanical desorption of an infinitely long lattice chain: Re-entrant phase diagrams

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