DISSERTATION

______________________________________________________________________ Introduction
Externally applied potentials affect already formed SAMs, causing the change of their
structure 16 , change of wettability 17 or desorption 18,19 . The desorption of SAMs can occur by
applying rather high positive or negative potentials. Nevertheless, the potential value required
to invoke SAM desorption depends on the type of alkylthiols used (length of the alkyl chain,
head group repulsion) and the coverage, since they influence the stability of the SAM 12 . Longer
alkylthiols and more compact layers are more stable SAMs and therefore, more difficult to
desorb. Furthermore, the possibility of controlling SAM formation by applying an external
potential was observed in the 1990s 20 . Application of anodic constant potentials seems to
accelerate the kinetics of SAM formation 13,21-24 . However, this phenomenon is still poorly
understood.
Figure 1.2. Self-assembly on an electrode surface occurs through two phases: a) in the first
phase (lying phase) molecules randomly lie on the surface, and in b) the second phase
(healing phase) they slowly reorganize to form highly compact monolayers.
1.1 Thiol self-assembling 5