  The persistence length of macromolecules is one of their basic
characteristics, describing their intrinsic local stiffness. However, it is
difficult to extract this length from physical properties of the polymers,
different recipes may give answers that disagree with each other. Monte Carlo
simulations are used to elucidate this problem, giving a comparative discussion
of two lattice models, the self-avoiding walk model extended by a bond bending
energy, and bottle-brush polymers described by the bond fluctuation model. The
conditions are discussed under which a description of such macromolecules by
Kratky-Porod worm-like chains holds, and the question to what extent the
persistence length depends on external conditions (such as solvent quality) is
considered. The scattering function of semiflexible polymers is discussed in
detail, a comparison to various analytic treatments is given, and an outlook to
experimental work is presented.
