大自然生物，成為開發制動元件及人工智慧材料的靈感來源。聚（NIPAM-co-AM）水凝膠，利用其熱或光感應性特徵，創造了人工仿虹膜水凝膠。本研究合成了一系列的N-異丙基丙烯醯胺（NIPAM）和丙烯醯胺（AM）的共聚反應，化學交聯劑N，N'-亞甲基雙（丙烯醯胺）（Bis-Am）被用來改善機械性質和控制水凝膠的孔徑大小。為實現光控仿人工虹膜，聚多巴胺（PDA）被塗佈在水凝膠表面。NIPAM的優點是它具有低臨界溫度（LCST），合成的水凝膠能夠在不同溫度下進行膨脹/脫水的運動。為了研究孔徑大小和密度對合成的仿虹膜水凝膠性能的影響，我們合成了一系列具有不同孔隙的水凝膠。透過DMA分析結果，交聯度的增加可使得水凝膠的韌性上升，但卻使膠體減少了彈性。經由SEM分析可以觀察水凝膠的孔隙率，加入更多的交聯劑會使得孔隙變小，並導致體積的擴張受到限制。水凝膠孔徑大小，也會影響水凝膠的含水量和制動特性。 為了進一步研究所合成的水凝膠在制動器上的應用，本研究也合成了密度具有梯度分布的水凝膠條狀薄膜。探討了所合成條狀致動器的可逆性熱感應彎曲，結果顯示致動器具有快速的響應時間。所製備的人工虹膜水凝膠表面，使用聚多巴胺（PDA）塗層後，用近紅外光照射時，可顯示出快速且可逆的內徑和外徑括/縮小運動。在充足的水環境下，人工虹膜水凝膠的反應時間得到了明顯的改善。制動測試的結果顯示，擁有較小孔徑的水凝膠表現出更快的恢復速度。由研究成果顯示，本研究所製備的光/熱感應水凝膠，可期望未來在微型機械人及生物醫學領域中，皆能具有多種潛力的實際應用。

Our nature becomes a source of inspiration to develop artificial intelligent materials through external stimuli. On the basis of the thermal/photo responsive poly(NIPAM-co-AM) hydrogels, artificial iris-like hydrogels were created. To investigate the pore size effect on the improvement of artificial iris hydrogel, a series of N-isopropyacrylamine (NIPAM) and acrylamide (AM) copolymers was synthesized. Chemical crosslinker N,N'-methylene bis(acrylamide) (Bis-Am) was employed to improve mechanical qualities and also to control the pore size of the hydrogel. Polydopamine (PDA) was coated on the surface of hydrogels to synthesize the light-controllable artificial iris. Based on the lower critical temperature (LCST) of NIPAM hydrogels, the synthesized hydrogel performs swelling/deswelling motion at various temperatures. To investigate the effect of pore size and density on the performance of the synthesized iris-like hydrogels, a series of hydrogels with various porosities was fabricated and investigated. The DMA analysis results reveal that increasing crosslink content enhances the toughness but decreases the elasticity of the hydrogels. Results of SEM show that increase of crosslinker content makes the porosity of hydrogels smaller lead to the restriction of swelling volume. To study the thermal actuation of the synthesized hydrogels, hydrogel strip films with gradient densities were synthesized. Reversible thermally responsive U-shape bending and recovering of the fabricated strip actuators were investigated. Photo sensitive artificial iris hydrogels were achieved via the polydopamine (PDA) coating on the surface of hydrogels. NIR light induced reversible fast widening and closing of the fabricated artificial iris-like hydrogels were investigated. Furthermore, the response time of the artificial iris hydrogels was significantly improved under sufficient water environment. The actuation test concluded that smaller pore size of hydrogel exhibits faster recovery of actuation hydrogel. Based on the results, the predesigned photo/thermal responsive hydrogels are expected to show potential practical applications in micro robot and biomedical fields.

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