| 摘要: | 這項研究,我們積極探索研究電場對聚合物行為的影響,以提高膜的性能。藉由利用聚合物高分子和電場之間的相互作用,可以改變膜的形
態以提高其性能。該研究首先研究施加電場對聚偏氟乙烯( PVDF )結晶動力學的影響。在獲得基礎資訊後,下一步是研究如何將電場應用於傳統的聚合物膜製備方法。該研究重點聚焦在兩種類型的聚合物,叫做同質聚偏氟乙烯和更複雜的全氟共聚物全氟磺酸。
研究結果表明,電場通過加速晶體生長和減小晶粒大小,對 PVDF結晶起著重要作用。電場還有利於形成極性 γ 形晶體,這些晶體可以在低
於 160°C的溫度下結晶。Avrami 方程用於研究動力學行為並確定結晶活化能。從 Avrami 和熱力學參數來看,電場似乎通過降低活化能來加速結晶過程。
利用簡單和不耗能的技術(如 NIPS )可以通過電場改變聚合物形態。在 NIPS 方法中,池化過程是作為一種預處理方法,接著將澆鑄溶液
浸入水中以固化具有特定形態的膜。電場不僅影響膜內孔隙的大小和分佈,還改變了結晶結構和方向。形態的變化影響膜保持離子液體的能力以及它們在膜上的傳輸。
該研究還檢視了施加電場對隨機共聚物(如全氟磺酸)的聚合物形態、液相和質子傳輸性質的影響。電場對形態和性質的影響尤其在兩個系
列的全氟磺酸膜中較為明顯,其中一個是直接從製造溶液中製備的,另一個是在 NMP 溶液中重新溶解的。電場增加了結晶度並擴大了離子團簇,從而產生更快的離子傳輸性質。;The investigation aimed to elucidate the profound influence of electric fields on polymer behavior, with the objective of enhancing membrane properties. By harnessing the strong interaction between polymer molecules and
electric fields, strategic modifications can be made to the morphology of membranes, leading to substantial enhancements in their properties. The study was initiated by scrutinizing the impact of electric perturbation on the
crystallization kinetics of polyvinylidene fluoride (PVDF). Armed with this foundational understanding, subsequent phases of the research delve into techniques for incorporating electric fields into traditional polymer membrane
preparation methods. Specifically, the investigation was focused on two distinct types of polymers: the simple homopolymer PVDF and the polymer functionalized with ionic groups, exemplified by Nafion.
The outcomes of the research underscored the considerable role played by electric fields in PVDF crystallization. This role was manifested through accelerated crystal growth and the reduction in spherulite size. Additionally, the electric field facilitated the creation of the polar γ-form crystals, which could be crystallized at temperatures below 160°C. The pplication of the Avrami equation to examine kinetic behavior and ascertain crystallization energy activation highlighted that the electric field expedited the crystallization process by reducing the energy activation threshold.
The modification of polymer morphology through the implementation of electric fields can be effectively achieved through simple and low-energy techniques, such as nonsolvent-induced phase separation (NIPS). In the NIPS method, the application of electric fields served as a pre-treatment step, followed by immersion of casting solutions in water to solidify membranes with tailored morphologies. It is noteworthy that the electric field exerted an influence not only on the size and distribution of voids within the membranes but also on crystalline structures. These changes in morphology hold significant implications for the membrane′s ability to retain ionic liquids and facilitate their transport across the membranes.
Furthermore, the study delved into the ramifications of an applied electric field on the morphologies, states of water, and proton transport properties of random copolymers, typified by Nafion. The effects of the electric field on morphologies and properties are particularly pronounced in two series of Nafion membranes: those directly prepared from manufacturing solutions and those redissolved in N-methyl-2-pyrrolidone (NMP) solutions. The electric field amplified crystallinity and enlarges ionic clusters, ultimately culminating in heightened ion transport properties. |
