  Dislocations in soft condensed matter systems such as lamellar systems of
polymers, liquid crystals and ternary mixtures of oil, water and surfactant
(amphiphilic systems) are described in the framework of continuum elastic
theory. These systems are the subject of studies of physics, chemistry and
biology. They also find applications in the industry. Here we will discuss in
detail the influence of dislocations on the bulk and surface properties of
these lamellar phases. Especially the latter properties have only been recently
studied in detail. We will present the experimental evidence of the existence
of screw and edge dislocations in the systems and study their static properties
such as: energy, line tension and core structure. Next we will show how does
the surface influence the equilibrium position of dislocations in the system.
We will give the theoretical predictions and present the experimental results
on thin copolymer films, free standing films of liquid crystals and smectic
droplets shapes. The surface is deformed by dislocations. These deformations
are known as edge profiles. Surface deformations induce elastic interactions
between edge dislocations. A new phenonenon discussed in our paper is the
fluctuations induced interactions between edge dislocations.At suitable
conditions edge dislocations can undergo an unbinding transition. Also a single
dislocation loop in a smectic freely suspended film can undergo an unbinding
transition. We shall also compute the equilibrium size of the loop contained
between two hard walls. Finally we will discuss the dynamical bulk properties
of dislocations such as: mobility (climb and glide),permeation, and helical
instability of screw dislocations. Lubrication theory will also be discussed.
