The name is absent

introduction of surface forces, and the competition between fluid-surface and fluid-
fluid forces, can lead to interesting surface-driven phase changes. These include new
kinds of phase transitions not found in the bulk phases, such as layering and wetting,
as well as shifts in transitions (e.g. freezing, gas-liquid, liquid-liquid) that are familiar
from bulk behavior.

Experimental techniques to study the microstructure of these systems are ham-
pered by the molecular scale. Molecular simulations are computationally expensive
and even with all the given computational advancement, are limited to short chain
molecules with simple interactions. Hence, a number of theoretical models have been
developed to study inhomogeneous systems. The earlier ones such as scaling∕mean
field theories were limited to a particular system, such as scaling theory of Alexan-
der [51] and de Gennes [52] for polymer brush. Moreover, the scaling theories do not
calculate the detailed structure, accurately. A more systematic theoretical approach
for the equilibrium properties of inhomogeneous polymers, has been the self consis-
tent field theory (SCFT). Using statistical mechanics, the Gaussian chain model [53]
for long polymer chains can be solved using the self-consistent field theory (SCFT)
introduced by Edwards [54]. In this approach, the molecular interactions are treated
by a mean field which has to be evaluated numerically.

Another important class of theories that have recently been applied to study inho-
mogeneous polymer systems are the density functional theories (DFTs) [55]. These
theories include more physics than mean field theories and SCFTs, as they retain

20

<<   29   30   31   32   33   34   35   >>

More intriguing information