近年來，隨著3D列印技術的蓬勃發展，對於列印材料的需求也與日俱增。水凝膠為目前最常使用的3D列印材料之一，然而其較易受到環境溫度和濕度的影響，穩定性及耐久度稍嫌不足。為克服此劣勢，我們採用了深共熔溶劑來取代水作為新媒介，其具有低揮發性和較大的工作溫度範圍，有望能夠解決水容易蒸發之問題。

在3D列印材料的開發當中，流變性質的調控也至關重要。纖維素奈米晶體被廣泛用作為流變塑形劑，用以調控材料之流變性質。它能使材料在聚合(固化)之前便形成具一定機械強度之凝膠，有助於保持列印過程中形狀的完整性。此外，纖維素奈米晶體具有高度縱橫比之性質，在列印過程中，能夠順著剪切應力的方向排列，進而降低流動的困難度，呈現剪切稀化的特性，利於確保列印的連續和穩定性。

然而，目前較少研究採用深共熔溶劑搭配纖維素奈米晶體開發3D列印材料，因此對材料流變性質的控制和分散製程的選擇仍然是一個重要的議題。為此，我們開發了一種新型的分散製程，透過加熱和剪切作用促進纖維素奈米晶體於深共熔溶劑中均勻分散。這種方法能在較低之流變塑形劑添加含量下，便促使高機械強度凝膠的形成，為後續單體的添加提供更大的空間和自由度。此外，我們也追蹤及記錄了一系列製程參數對材料流變性質和分散行為的影響，以實現更精準、便利地控制材料之流變特性，從而促進3D列印技術的應用。我們也希望透過本研究，為後續深共熔溶劑/纖維素奈米晶體凝膠材料的開發提供一些參考和幫助。

In recent years, with the flourishing development of 3D printing technology, the demand for printing materials has been increasing rapidly. Hydrogels are among the most commonly used materials for 3D printing. However, they are susceptible to environmental temperature and humidity, resulting in limited stability and durability. To overcome this issue, we have adopted deep eutectic solvents (DESs) as a replacement for water, serving as a novel dispersed medium. These solvents possess the advantage of low volatility and a wider operating temperature range, which provide hope for resolving the problem of water evaporation.

The precise control of rheological properties is crucial in the development of 3D printing materials. Cellulose nanocrystals (CNCs) have emerged as widely used rheological modifiers for modulating the rheological behavior of materials. They facilitate pre-gel formation with superior mechanical strength prior to polymerization (solidification), ensuring shape integrity during the printing process. Additionally, the distinctive high aspect ratio of CNCs enables them to align with the shear direction during the printing process, alleviating flow difficulties and exhibiting shear thinning behavior to promote continuous and stable extrusion.

However, research on integrating DESs and CNCs for developing 3D printable materials remains limited. Consequently, precise control of materials' rheological properties and selecting suitable dispersion processes continue to pose significant challenges. In light of this, we have devised a novel dispersion process employing a thermal and a shear treatment to facilitate the uniform dispersion of CNCs within DESs. This approach enables the formation of high-strength pre-gel at lower concentrations of rheological modifiers, providing ample space and flexibility for subsequent monomer incorporation. Furthermore, we have investigated the effect of various process parameters on rheological properties and dispersion behavior, aiming to achieve precise and convenient control over the rheological behavior of materials, thereby advancing the application of 3D printing. Our research strives to provide some guidelines and assistance for future development in DESs/CNCs materials.

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