以去摻雜聚苯胺薄膜製備網狀銀金屬與成長機制的探討

Abstract

聚苯胺具有氧化還原的性質，中間氧化態的聚苯胺其氧化還原電位可以將銀離子還原成銀原子。此外，我們發現作為凝膠化抑制劑(gel inhibitor)加入聚苯胺溶液中的HPMI(heptamethyleneimine)同樣可以還原銀離子。在我們的系統中，聚苯胺與HPMI都與銀金屬的還原有密不可分的關係。 本研究以鹼式中間氧化態聚苯胺(emeraldine base, EB)製備薄膜，利用薄膜作為基板於硝酸銀的甲醇溶液中還原出網狀銀金屬。本文旨在探討此系統中銀網結構成長機制。經XRD及TEM的鑑定發現此網狀銀金屬的晶體方位排列具有高度的一致性，且主要晶面為{111}面族並以<110>的晶面成長方向。我們建立起銀金屬的成核成長模型，透過對於成核成長速度的調控，我們可以成長出不同型態的銀金屬，包含三角或六角片狀、銀帶、銀網等結構。另外藉由調控EB薄膜中的HPMI含量，來釐清聚苯胺與HPMI在反應過程中各自的角色。

Polyaniline has redox properties. Emeraldine state of polyaniline can be the reducing agent to silver ions. Furthermore, we find that HPMI (heptamethyl-leneimine), as a kind of gel inhibitor for polyaniline solution, is the reducing agent to silver ions, too. In our systems, both polyaniline and HPMI are important to the reduction of silver ions. In this study, emeraldine base(EB) is made into films. We put the film into silver nitrate methanol solution to make mesh-liked silver. This thesis is aimed to investigate the mechanism of the mesh-like silver. Through XRD and TEM diffraction pattern, it was found that the structure of the mesh-liked silver has a high degree of crystal orientation consistency, and the main crystal faces are the {111} face family and the <110> crystal face growth direction. We constructed the nucleation-growth competition model. Through the control of nucleation and growth rate, we can synthesize different type of silver, included triangular or hexangular silver plate, belt-like silver and mesh-like silver. Also, we adjusted the content of HPMI in the EB film to clarify the role of polyaniline and HPMI in the experiments.