利用嵌段共聚物之模化電鍍製備導電高分子奈米列陣

Conjugated Polymer Nanoarrays from Templating of Block Copolymer via Electroplating

張瑋傑

指導教授 ： 何榮銘

國立清華大學/工學院/化學工程學系/碩士(2012年)

https://doi.org/10.6843/NTHU.2012.00198

摘要

具有特殊奈米型狀排列的物質近年來因為其奈米大小而備受重視。在我的實驗中以PS-PLLA嵌段共聚物形成一模板載具，藉由將PLLA鏈段去除掉後得到一奈米孔洞PS模板。再結合電鍍的方式，在導電ITO基板上，以3HT單體在孔洞中電聚合出P3HT，可以大規模製造具有排整性特殊結構的奈米P3HT。研究中以周期性升降電壓的方式，可控制電解液在孔洞中的濃度，使其維持一平衡濃度，確保在電鍍過程中，不會有溢出或未填滿的情況產生;後續也以核磁共振儀、霍式紅外儀器、表面元素分析等儀器去做鑑定，證明出合成出來的確實是P3HT。進一步的，除了柱狀結構以外，我們也努力得到一個三維網狀結構，在薄膜情況下須考慮介面以及厚度的問題，因此我們以一系列不同的厚度，在熱處理增加其移動性，以期望得到規則度高的三維網狀結構薄膜。有趣的是，在系統當中發現到熱裂解問題，並存在與厚度的相依性。如何精確控制熱處理時間，及厚度條件，是研究中需考慮到的因素，在透過上述方式後，我們也得到小範圍的特殊三維網狀結構，得以應用在後續的元件上。

關鍵字

嵌段共聚物 ； 導電高分子 ； 電沉積聚合

並列摘要

Nanostructured materials have drawn intensive attention because of their unique properties resulting from nanoscale features. One of the convenient ways to generate nanostructured materials is to use self-assembled degradable block copolymers (polystyrene-b-poly(L-lactide) (PS-PLLA)) after hydrolysis as templates for the reactions carrying out within the templates (i.e., the concept of nanoreactor). In this study, we focused on the execution of electroplating of low-cost and large-area poly-3(hexylthiophene) (P3HT) within the nanoporous PS to demonstrate the feasibility and generality of fabricating nanostructured thin films with P3HT nanoarrays. The electroplating process for the polymerization of 3-hexylthiophene (3HT) monomer was carried out within the PS template on the top of ITO glass by controlling the diffusion of reactive monomers along the nanochannels driven by capillary force. Instead of using continuous electroplating, a pulse mode having a periodic electroplating and a diffused sequence was applied to equalize the concentration gradient of 3HT monomer within nanopores. As a result, electropolymerization of P3HT can be carried out in the electroplating conditions with micro current, as evidenced by chronoamperogram recorded in the pulse plating. Moreover, the formation of templated P3HT was characterized by using Fourier transform infrared spectrometry (FTIR), X-ray photoelectron spectroscopy (XPS) and Nuclear Magnetic Resonance Spectroscopy (NMR). Herein, we demonstrate a novel way for the formation of conducting polymer nanoarrays by the integration of nanopatterning and electroplating; it is appealing in the practical application such as solar cell, flexible electrode and field-emitted display.
In addition to the fabrication of cylindrical P3HT nanoarrays, we aim to fabricate large-size thin films with gyroid-forming PS-PLLA diblock copolymer. The thin-film morphologies after casting are very different to that of bulk samples from the self-assembly of the PS-PLLA at which disorder-like microphase-separated texture is usually found. As a result, thermal annealing was carried out to induce the ordering of the cast samples. Interestingly, the thermal-annealed morphologies are strongly dependent upon the film thickness at which the confinement effect on self-assembled morphologies might be effective once the film thickness reaches a minimum. Consequently, the formation of bicontinuous phase can be successfully achieved by thermal annealing with controlled annealing time and suitable thickness due to the increasing of mobility for reorganization of self-assembled morphologies to reach energetic stable state. To achieve the formation of gyroid texture (i.e., higher-order morphology), it is necessary to increase the annealing time or to enhance the chain mobility of BCPs. Nevertheless, it is noted that thermal degradation of PLLA may occur once the thermal annealing is over 2hrs or the annealing temperature is over 220oC, as evidenced by the results of gel permission chromatography(GPC) so as to result in the formation of micelle texture.

並列關鍵字

block copolymer ； conjugated polymer ； electroplating

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