4-乙烯基吡啶-苯乙烯共聚物多孔纖維氣凝膠的製備及應用

Abstract

靜電紡絲已是一項被公認能製備出極細纖維的技術，本研究主要是將靜電紡絲結合相分離法和氣凝膠技術，來製備出一由多孔纖維所構成的具極低密度、高孔隙度和低熱傳導係數的氣凝膠，來做為油汙吸附及隔熱之應用。 本實驗使用包含高、低極性單元的4-乙烯基吡啶-苯乙烯共聚物 (S4VP) 作為材料，再利用本實驗室所歸納出的成孔機制和條件，選擇一高沸點親水的溶劑和另一低沸點疏水的溶劑，藉由這兩種溶劑組合，在纖維表面上可以形成多孔結構，並且觀察纖維截面的型態可以發現這些孔洞是由外貫穿到內部，在纖維表面上形成孔洞結構除了可以大幅提升比表面積外，還對於形成極低密度的氣凝膠有很大的幫助。 本研究不只成功將原先電紡出的2D纖維薄膜變成3D立體網狀的氣凝膠結構，提升了孔隙度和比表面積外，更是做出密度僅有3.16 mg/cm3且熱傳係數接近空氣的氣凝膠，其在油汙吸附上更是有著優異的表現。氣凝膠獨特的多孔網狀結構，包含層狀間的巨孔結構、纖維和纖維之間的間隙和纖維表面上的孔洞，除了有更多空間使油汙能進入到孔洞內部，明顯提升了油汙吸附量外，也使熱的傳導受到限制，因此大幅降低其熱傳導係數。本研究形成氣凝膠所使用的分散溶劑是水和酒精，製程對環境十分友善而且步驟相較傳統製作氣凝膠方法簡易，省去了傳統繁瑣耗時的過程，且可藉由調整不同纖維薄膜的重量、不同形貌的纖維來製作出不同密度的氣凝膠，也能藉由不同模具來製作出不同形狀的氣凝膠，使其有了更多方面應用的潛力。

Electrospinning is a recognized technique for producing extremely fine fibers. In this study, we combined electrospinning with phase separation and aerogel technology to fabricate a porous fiber-based aerogel with ultra-low density, high porosity, and low thermal conductivity for oil adsorption and thermal insulation applications. The material used in this experiment was Poly(4-vinylpyridine-co-styrene), (S4VP) containing high and low polarity units. Based on the pore formation mechanism and conditions established in our laboratory, we selected a high-boiling-point hydrophilic solvent and a low-boiling-point hydrophobic solvent. By combining these two solvents, we could form a porous structure on the fiber surface. The cross-section of the fibers revealed that these pores penetrated from the outer to the inner regions. Forming pore structures on the fiber surface not only significantly increased the specific surface area but also greatly facilitated the formation of ultra-low-density aerogels. This study not only successfully transformed the original 2D electrospun fibrous membrane into a 3D three-dimensional mesh-like aerogel structure, greatly enhancing the porosity and specific surface area. The resulting aerogel had a density of only 3.16 mg/cm3 and a thermal conductivity close to that of air, making it highly promising for oil adsorption applications. The unique porous network structure of the aerogel, including macropores between layers, gaps between fibers, and holes on the fiber surface, not only provided more space for oil to enter the pores, greatly increasing the oil absorption capacity but also restricted heat conduction, leading to a significant reduction in thermal conductivity. The dispersion solvents used in the aerogel formation process were water and alcohol, making the process environmentally friendly. It also simplified the traditional laborious and time-consuming steps of aerogel fabrication. Additionally, by adjusting the weight of different fiber films and using fibers with different morphologies, aerogels with varying densities can be produced. Moreover, using different molds enabled the production of aerogels with different shapes, expanding their potential for various applications.