聚(3,4-二氧乙烯基噻吩)/聚對苯乙烯磺酸 與銀之複合材料製備

Abstract

本論文證實PEDOT:PSS具有還原的能力，並利用此一特性，搭配過硫酸銨具有間接還原力的性質，發展出一套在PEDOT:PSS上成長樹枝狀結構之銀金屬的製備方法。本論文根據實驗結果提出一套模型，解釋本系統中樹枝狀銀金屬之成長機制與PEDOT:PSS所扮演的角色。 在去除EDOT單體之PEDOT:PSS水溶液中，加入硝酸銀，此時銀金屬會在PEDOT的表面生成，隨著反應時間的進行，PEDOT上被奈米銀全部佈滿。經XRD鑑定，吾人證實PEDOT:PSS具有還原能力。 在PEDOT:PSS/硝酸銀/過硫酸銨系統中，PEDOT在初期的反應中提供電子讓銀離子還原。吾人經由XRD繞射及TEM圖鑑定銀晶體，觀察其形態，認為過硫酸銨在PEDOT提供初始之銀晶核後便參與還原反應，故在此系統中，還原分別來自於PEDOT與過硫酸銨的貢獻，還原反應之速率由擴散速率所決定，提供此一擴散障礙的是聚對苯乙烯磺酸(PSS)，而擴散障礙即為生成樹枝狀銀金屬之關鍵，反應中期會發生 Ostwald Ripening之機制，藉以穩定系統的能量，最後生長出樹枝狀結構之銀金屬。而在PEDOT:PSS/硝酸銀/過硫酸鉀之系統中，亦驗證了過硫酸鹽的間接還原能力以及此一樹枝狀銀金屬合成方式的可行性。 本論文即以此合成方法製備樹枝狀銀金屬/PEDOT:PSS之複合材料。

關鍵字：過硫酸銨、奈米銀、樹枝狀結構、複合材料

This paper confirmed that PEDOT: PSS is a reductant and exploited the reducing ability of both PEDOT:PSS and ammonium persulfate to develope a dendritic silver and PEDOT:PSS composite. We proposed a model about the growth mechanism of dendrite in PEDOT:PSS based on experimental results by a series of TEM image. Because the EDOT could be reducing agent, we added the silver nitrate to the purified PEDOT: PSS aqueous solution. We found that silver would grow on the surface of PEDOT. When the reaction runs for 10 min, PEDOT would be covered by the silver nanoparticles. We confirmed that PEDOT: PSS has the reducing ability by XRD.

In the PEDOT: PSS / silver nitrate / ammonium persulfate system, the growth mechanism of dendritic silver is proposed to be as follows. At first, PEDOT would reduced silver ions to silver nanoparticles on its surface. And then APS would join this reducing reaction because it took the nuclei which PEDOT reduced as a growing point. This reaction is controlled by diffusion and the formation of dendritic silver is explained by Orientation Attachment & Ostwald Ripening mechanisms.

Keywords: PEDOT:PSS, ammonium persulfate, silver nanoparticles, dendrite, composite