| 摘要: | 本研究利用循環伏安法(Cyclic Voltammetry, CV)和掃描式穿隧電子顯微鏡(Scanning
Tunneling Microscope, STM)探討兩個部份，首先丙烯醯胺十一烷酸(11-acryloylamino
undecanoic acid, AAUA)是一種多功能可聚合界面活性劑，目前已用作醫療器材的塗層，
因此對於 AAUA 在金屬基底上的吸附多加了解可以加強其應用。研究中透過改變電位
及陰離子研究其吸附行為，結果闡明分子間除了脂肪族基團之間的凡得瓦力外，羧酸
基團和丙烯醯胺基團之間的氫鍵也可以幫助 AAUA 分子在金電極上的排列，形成有序
分子結構。在負電位時 AAUA 通常為平躺的有序結構，但到正電位時會進行結構轉換
變為直立無序狀；在不同電解質中，由於陰陽離子的改變，使得陰陽離子跟分子的作
用力不同，因此 PBS 的陰離子可以與分子形成氫鍵作用力，進而形成獨特的格子狀結
構，而在不同的電解質中都擁有條紋狀結構但由於分子與陰離子的共吸附使得其有序
條紋狀寬度會有所差異。
除 了 AAUA 外也有 探 討 其 他 分 子 的 吸 附 像 是 Acryloylglycine (2-AG)、6-
acrylamidohexanoic acid (6-AHA)及 sodium 11-acrylamidoundecanoate (Na-AAUA)，不同
長度的脂肪族基團跟金的作用力不同，透過研究結果可以得知當碳鏈越長時跟金的作
用力越好，越容易形成有序分子膜，而在正電位時都會轉換成無序結構，此時當分子
結構越小時，越容易從無序狀回到有序的分子結構。而鹽類 Na-AAUA 跟 AAUA 相比
其吸附行為沒有明顯的不同，在 PBS 中一樣擁有獨特的格子狀，只是條紋狀結構的寬
度會有所差異，推測是與陰離子的吸附有關。
第二部分則是揭示了鐵在金電極上的成核和薄膜生長過程，透過研究結果可以得
知鐵會優先沉積於金的(1 × 1)結構，也就是 FCC 的晶格結構且會形成 moiré pattern 排
列，鐵會隨著沉積量的增加逐漸有第二層的鐵吸附。當使用分子修飾電極後，鐵在金
電極上的沉積電位和沉積量會被延遲及減低，且由於在正電位時分子會改以直立狀，
其介電特性影響電極介面的電荷傳輸快慢，導致 Fe2+ 較難轉換為 Fe3+。
;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. |
