Shape of a Random‐Flight Chain

1971 ◽  
Vol 55 (1) ◽  
pp. 335-344 ◽  
Author(s):  
Karel Šolc
Keyword(s):  
Random Flight

Theory of the stabilization of colloids by adsorbed polymer

1974 ◽  
Vol 337 (1611) ◽  
pp. 509-516 ◽  
Keyword(s):  
Plane Surface ◽  
Analytic Form ◽  
Polymer Chains ◽  
Contour Length ◽  
Link Length ◽  
Excluded Volume Effects ◽  
Adsorbed Polymer ◽  
Random Flight ◽  
The Stability ◽  
Simple Analytic Form

The configurational free energy of random flight polymer chains adsorbed by one end onto a plane surface as a function of the distance from a parallel plane surface is expressed to a good approximation in simple analytic form. The result is used to discuss the stabilization of a colloid suspension by adsorbed polymer. According to this theory two types of aggregation of colloid particles may occur. If LI < AS/2π 3 NkT , where l is the link length and L the contour length of a polymer chain, A is the Hamaker constant, N /S is the number of adsorbed polymer chains per unit area and kT is the Boltzman constant multiplied by temperature, the particles adhere closely, but if AS/2π 3 kT < IL < AS/nkT lg 2N a looser association is formed. It is expected that the presence of excluded volume effects would greatly increase the stability against the looser association.

‘Random-flight’ dispersal in tropical fruit-feeding butterflies? High mobility, long lifespans and no home ranges

2015 ◽  
Vol 40 (6) ◽  
pp. 696-706 ◽  
Author(s):  
NICHOLAS C. MARCHANT ◽  
ARI PURWANTO ◽  
FRANSISKUS A. HARSANTO ◽  
NICHOLAS S. BOYD ◽  
MARK E. HARRISON ◽  
...  
Keyword(s):  
High Mobility ◽  
Home Ranges ◽  
Tropical Fruit ◽  
Random Flight

Ballistic and diffusive random walks in confinement

2005 ◽  
Vol 899 ◽  
Author(s):  
Pierre Levitz ◽  
D. Grebenkov ◽  
D. Petit ◽  
C. Vigouroux
Keyword(s):  
Porous Materials ◽  
Biological Fluids ◽  
Exit Time ◽  
Colloidal Suspensions ◽  
First Exit Time ◽  
Heterogeneous Catalytic ◽  
Random Flights ◽  
Brownian Particles ◽  
Interfacial Confinement ◽  
Random Flight

AbstractPorous materials, concentrated colloidal suspensions are example of confining systems developing large specific surface and presenting a rich variety of shapes. Such an interfacial confinement strongly influences the molecular dynamics of embedded fluids and the diffusive motion of entrapped Brownian particles. An individual trajectory near the interface can be described as an alternate succession of adsorption steps and random flights in the bulk. Statistical properties of these random flights in various interfacial confining systems are determinant to understand the full transport process. Related to first passage processes, these properties play a central role in numerous problems such as the mean first exit time in a bounded domain, heterogeneous catalytic reactivity and nuclear magnetic relaxation in complex and biological fluids. In the present work, we first consider the various possibilities to connect two points of a smooth interface by a random flight in the bulk. Second, we analyze at the theoretical and experimental points of view a way to probe Brownian flights statistics. Implications concerning diffusive transport in disordered porous materials are discussed.

CONFORMATION AND CONFINEMENT ENERGY OF INTERACTING END-GRAFTED MOLECULES

2012 ◽  
Vol 04 (01) ◽  
pp. 1250008
Author(s):  
YUAN LIN ◽  
SHUHUAI YAO
Keyword(s):  
Closed Form ◽  
Gold Surface ◽  
Thermally Induced ◽  
Closed Form Solutions ◽  
Flexible Molecules ◽  
The Core ◽  
Grafting Density ◽  
Random Flight Model ◽  
Random Flight ◽  
Flight Model

The conformation and confinement energy of flexible molecules grafted on a surface are considered in the framework of classical "random flight" model. Interactions among molecules are included in the analysis and closed form solutions are presented for two limiting cases where the core interaction is either very strong or very weak. The case of stiff molecules is also considered via a different approach where their thermally-induced bending deformations, as well as interactions, have been taken into account. We will demonstrate that, under seemingly identical conditions, the behavior of stiff molecules is quite different from that of flexible ones. Predictions obtained here agree with various experimental observations on the grafting density of single- and double-stranded DNAs on a gold surface.

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