Statistics of macromolecular solutions trapped in small pores

Daoud, M.; Gennes, P. G. de

doi:10.1051/jphys:0197700380108500

Cited by 551 publications

(651 citation statements)

References 11 publications

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“…Before introducing the extended de Gennes regime, we first review the blob model 5,6 for the classic de Gennes regime, where the chain is considered as a string of blobs with size of D (Figure 1). Because of excluded volume (EV) interactions, these blobs avoid each other, and the subchain within a blob follows the Flory scaling, L blob ∼ D 5/3 , where L blob is the contour length within a blob.…”

Section: Introductionmentioning

confidence: 99%

Extended de Gennes Regime of DNA Confined in a Nanochannel

2014

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Scaling regimes for polymers confined to tubular channels are well established when the channel cross-sectional dimension is either very small (Odjik regime) or large (classic de Gennes regime) relative to the polymer Kuhn length. However, experiments of confined polymers using DNA as a model system are usually located in the intermediate region between these two regimes. In the literature, controversy exists regarding the existence of the extended de Gennes regime in this intermediate region. Here we use simulations and theory to reconcile conflicting theories and confirm the existence of extended de Gennes regime. We show that prior work did not support the notion of this regime because of the use of a wrong confinement free energy. In a broad sense, the extended de Gennes regime corresponds to the situation when excluded volume interaction is weaker than thermal energy. Such a situation also occurs in many other cases, such as semidilute polymer solutions and polymers under tension. This work should benefit the practical applications of nanochannels to stretch DNA, such as deepening the understanding of the relationship between the chain extension and channel size and providing the scaling behaviors of recoiling force for DNA at the entrance of nanochannels.

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Section: Introductionmentioning

confidence: 99%

Extended de Gennes Regime of DNA Confined in a Nanochannel

2014

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“…DNA has played a key role in the experimental tests of theories of a polymer confined to a slit [1][2][3][4][5][6][7][8][9][10][11][12][13][14] or a channel [15][16][17][18][19][20][21][22][23][24][25][26][27], in particular the models by de Gennes and coworkers for weak confinement [28,29] and Odijk for strong confinement [30,31]. The key results of this body of work have been summarized in several recent reviews [32][33][34].…”

Section: Introductionmentioning

confidence: 99%

“…The models developed for channel-confined polymers make scaling law predictions for the confinement free energy, F , the average size of the confined chain, X , and the variance about that size, δX 2 , for a neutral polymer confined by hard walls [29][30][31][39][40][41]. In some cases, the prefactors for the scaling laws are known exactly [41][42][43].…”

Section: Introductionmentioning

confidence: 99%

Wall depletion length of a channel-confined polymer

Cheong

Dorfman

2017

Phys. Rev. E

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Numerous experiments have taken advantage of DNA as a model system to test theories for a channel-confined polymer. A tacit assumption in analyzing these data is the existence of a well defined depletion length characterizing DNA-wall interactions such that the experimental system (a polyelectrolyte in a channel with charged walls) can be mapped to the theoretical model (a neutral polymer with hard walls). We test this assumption using pruned-enriched Rosenbluth method (PERM) simulations of a DNA-like semiflexible polymer confined in a tube. The polymer-wall interactions are modeled by augmenting a hard wall interaction with an exponentially decaying, repulsive soft potential. The free energy, mean span, and variance in the mean span obtained in the presence of a soft wall potential are compared to equivalent simulations in the absence of the soft wall potential to determine the depletion length. We find that the mean span and variance about the mean span have the same depletion length for all soft potentials we tested. In contrast, the depletion length for the confinement free energy approaches that for the mean span only when depletion length no longer depends on channel size. The results have implications for the interpretation of DNA confinement experiments under low ionic strengths. * dorfman@umn.edu

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“…P.G. de Gennes et M. Daoud [43] ont montré que des chaînes de polymères neutres rentrent dans des fentes ou des canaux dès que la longueur de corrélation ξ de la solution semi-diluée est inférieure à D (Figure 13). Pour des pores de Vycor, dont le rayon est de 3.5 nm, cela correspond à des concentrations supérieures à 20% (en poids/volume).…”

Section: Polymères Confinésunclassified

Diffusion de neutrons aux petits angles appliquée aux études d'interfaces et de systèmes confinés

Auvray¹,

Brûlet

2007

Journées de la Neutronique

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Résumé. La diffusion de neutrons aux petits angles (DNPA) permet de sonder la matière aux échelles spatiales allant de 0.5 et 50 nm en déterminant les grandeurs moyennes qui caractérisent la taille et la forme des objets ainsi que leurs interactions. Elle s'applique à divers systèmes, polymères, colloïdes, pores dans les solides ou amas dans les alliages...Elle permet d'étudier l'organisation en volume de ces systèmes, mais aussi en couches minces, sur des couches adsorbées ou greffées et même dans des milieux confinés. Ce cours expose les différentes grandeurs mesurables et les méthodes à utiliser pour y accéder. En particulier seront abordées les notions de facteur de forme et de facteur de structure et les différentes façons de jouer avec le contraste pour déterminer les structures d'objets complexes et leurs interactions. Ces notions seront d'abord appliquées à des exemples classiques d'études de systèmes poreux et de fondus de polymères. Ensuite, plusieurs exemples illustreront l'application de la diffusion de neutrons aux études de polymères aux interfaces ou confinés.

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Statistics of macromolecular solutions trapped in small pores

Cited by 551 publications

References 11 publications

Extended de Gennes Regime of DNA Confined in a Nanochannel

Extended de Gennes Regime of DNA Confined in a Nanochannel

Wall depletion length of a channel-confined polymer

Diffusion de neutrons aux petits angles appliquée aux études d'interfaces et de systèmes confinés

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