dc.description.abstract | Cyclic voltammetry (CV) and scanning tunneling microscope (STM) were used to explore
the adsorption of 11-acryloylamino undecanoic acid (AAUA) and deposition of iron on an
ordered Au(111) electrode. AAUA, a multifunctional polymerizable surfactant for medical
devices, has an acrylamide and carboxylic acid at the two ends linked by aliphalic chains. Its
adsorption on Au electrode was studied, revealing the crucial role of potential contro and anion
coadsorption in guiding the spatial structure of AAUA. In addition to the van der Waals forces
between aliphatic groups, the hydrogen bonds between carboxylic acid groups and acrylamide
groups can also help its adsorption on Au. The arrangement of AAUA molecules on the gold
electrode forms an ordered molecular structure. At negative potential, AAUA usually has an
ordered structure, but when it reaches positive potential, it will undergo structural
transformation and become an upright disordered state. In different electrolytes, due to the
change of anions and cations, the forces between anions and molecules are different, so the
anions of PBS can form hydrogen bonding forces with molecules, thereby forming a unique
lattice-like structure. Different electrolytes have stripe structures, but due to the co-adsorption
of molecules and anions, the width of the ordered stripes will vary.
In addition to AAUA, the adsorption of other molecules such as Acryloylglycine (2-AG),
6-acrylamidohexanoic acid (6-AHA), and sodium 11-acrylamidoundecanoate (Na-AAUA) has
also been studied. Results show that the longer the carbon chain, the better the interaction with
gold and the easier to form an ordered molecular film. At positive potential, it converted into a
disordered structure. Among the molecules studied here, a smaller 2AG molecule was found to
return to an ordered molecular structure from a disordered state. The adsorption behavior of the
salt Na-AAUA is not significantly different from that of AAUA. It also has a unique grid
structure in PBS, but the width of the stripe structure is different. It is related to the adsorption
of anions.
iii
The second part reveals the nucleation and film growth processes of iron on the gold
electrode. Through the research results, it can be known that iron will preferentially deposit in
the Au(111) - (1 × 1) structure, suggesting that the lattice structure of FCC facilitated the
formation of a moiré pattern. Iron deposit gradually grew into a bilayer film with more negative
potential. On the modified Au electrode, the deposition potential shifted negatively and
deposition of iron became sluggish. Admolecules could change to the upright orientation at
positive potential, which impeded the charge transfer kinetics at the interface. The current due
to rdox Fe2+/3+ decreased with the length of organic modifier on the Au electrode. | en_US |