Schematic illustration.

Major Contributions

1. Introduction of Organic Macrocyclic Cavitands as Gatekeepers in Mixed Matrix Membranes
This work pioneers the incorporation of sulfocalixarene (SCA6), a purely organic macrocyclic cavitand, into Pebax®1657 membranes. SCA6 acts as a molecular gatekeeper, offering excellent compatibility with the polymer matrix and providing additional, size-selective transport channels for CO₂ molecules. This approach overcomes the traditional trade-off between permeability and selectivity in polymeric membranes for CO₂ capture.

2. Mechanistic Shift from Solubility-Dominated to Diffusivity-Dominated Gas Separation
Through systematic sorption and transport studies, it is demonstrated that the addition of SCA6 at optimal loading (1%) changes the gas separation mechanism in Pebax-based membranes. The mechanism shifts from being solubility-dominated to diffusivity-dominated, resulting in a significant increase in CO₂ permeability (by 45%) with only a minimal decrease in selectivity. This mechanistic insight is crucial for the rational design of next-generation gas separation membranes.

3. Achievement of Stable, High-Performance, and Industrially Relevant CO₂/N₂ Separation
The optimized Pebax/SCA6-1% membrane achieves a CO₂ permeability of 228.67 Barrer and a CO₂/N₂ selectivity of 70.01 under mixed gas conditions, surpassing the Robeson upper bound. The membrane also exhibits stable long-term performance over 108 hours, confirming its potential for practical industrial CO₂ capture applications.

主要貢獻

1. 首次將有機大環空穴分子作為混合基質膜的閘控劑
本研究首度將純有機的大環空穴分子—磺酸化杯芳烴（SCA6）引入Pebax®1657膜材，作為分子閘控劑。SCA6不僅與高分子基體具有優異的分子相容性，亦能提供額外且具尺寸選擇性的CO₂傳輸通道，成功突破傳統聚合物膜在CO₂捕集應用上滲透率與選擇性間的權衡限制。

2. 氣體分離機制由溶解主導轉變為擴散主導
藉由系統性的吸附與傳輸機制分析，證實在最佳SCA6添加量（1%）下，Pebax基膜的氣體分離機制由原本的溶解主導轉變為擴散主導，促使CO₂滲透率大幅提升（增加45%），而選擇性僅有極小幅度下降。此機制轉變對於新一代氣體分離膜的理性設計具有關鍵意義。

3. 穩定且具產業應用潛力的高效CO₂/N₂分離表現
最佳化的Pebax/SCA6-1%膜於混合氣體條件下展現CO₂滲透率228.67 Barrer及CO₂/N₂選擇性70.01，超越Robeson上限，並於108小時長時測試中維持穩定表現，顯示其於工業二氧化碳捕集應用的高度潛力。