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標題: | 溫度敏感性高分子之複合材料及其靜電紡絲之製備與應用:
Fe3O4/PNIPAAm 及 PEDOT:PSS/PNIPAAm Fabrication and Application of Thermo-responsive Polymer Composites and their Electrospun Fibers: Fe3O4/PNIPAAm and PEDOT:PSS/PNIPAAm |
作者: | Shih-Ru Huang 黃識儒 |
指導教授: | 林金福(King-Fu Lin) |
共同指導教授: | 邱文英(Wen-Yen Chiu) |
關鍵字: | 磁性,導電性,溫度敏感性,高分子複合材料,靜電紡絲, magnetic,conductive,thermo-responsive,polymer composite,electrospinning, |
出版年 : | 2015 |
學位: | 博士 |
摘要: | 本研究中的目標為製作出穩定的溫感性高分子複合材料及其靜電紡絲纖維。論文分為兩個部分,第一部分如第二章與第三章所述,主要為磁性奈米顆粒(四氧化三鐵;Fe3O4)與溫感性高分子PNIPAAm之複合材料與其靜電紡絲纖維之製備與性質探討。第二部分為導電性PEDOT:PSS與溫度敏感性高分子PNIPAAm之複合材料與其靜電紡絲纖維之製備與性質探討,以及鞘芯型靜電紡絲之研製,內容詳見第四章與第五章。
在第二章中,我們成功的製備了磁性與溫感性複合材料及其靜電紡絲纖維,也針對其溫感性與磁性做了研究。Fe3O4奈米顆粒是經由共沉澱法製作。再經由月桂酸改質表面之後,可以得到水中分散性佳的雙層肉桂酸改質Fe3O4奈米顆粒(DLF)。PNIPAAm與DLF/PNIPAAm複合材料之熱性質與溫感性質是用TGA與DSC量測。隨著DLF的含量上升,DLF與PNIPAAm之間的作用力會使LCST從33下降到31.25 ºC。有關pH值與複合材料濃度對LCST的影響也做了相關的實驗。DLF/PNIPAAm纖維可以利用靜電紡絲成功製成,其纖維直徑大約100到250奈米。DLF/PNIPAAm的複合材料與其靜電紡絲纖維之磁化率曲線幾乎重疊,其飽和磁化率也相同。在高於與低於LCST的情況下,DLF/PNIPAAm水溶液的磁性吸引有不同的表現。在高於LCST時,DLF/PNIPAAm的聚集會造成磁矩密度上升也增加了磁性吸引的能力。 在第三章中,利用靜電紡絲技術可以成功的製備UV交聯型磁性溫感性複合材料(MTC)纖維膜。Fe3O4是利用共沉澱法製成,PNIPAAm是用氧化還原起始方式製備。為了要提供交聯能力,我們引入DPHA為交聯劑,也添加了光起始劑與Fe3O4和PNIPAAm混合在乙醇溶液中當作靜電紡絲溶液。經過了靜電紡絲與UV交聯的過程,可製成MTC纖維膜。其溫感性可用DSC與溶脹比率試驗量測。由於絲狀結構的緣故,複合材料纖維膜的吸水能力與溫感性都比塊狀結構佳。利用SEM與TEM可觀察纖維型態而磁性則可利用SQUID來量測,得到飽和磁化率的質會正比於Fe3O4的含量。溫度相關磁性的測試是將許多小片MTC纖維膜置於溫度高於和低於LCST的水中,在不同的磁場強度下觀察其吸引的表現。結果收縮的MTC纖維膜有較佳的磁性吸引能力。在25 ºC與37 ºC之Vitamin B12藥物釋放實驗中,含有藥物的MTC纖維膜在37 ºC時,藥物會有突釋現象,而在25 ºC下則會逐漸擴散出藥物。在經過hyperthermia過程後,含藥物的MTC纖維膜會加速釋放藥物,這是因為熱所產生的相變化收縮導致的。 在第四章中,我們利用靜電紡絲製程,具溫感性與導電性的高分子複合材料薄膜與其靜電紡絲纖維膜可以成功製備。熱交聯型共聚物poly(N-isopropylacrylamide-co-N-methylol acrylamide) (PNN)可以利用氧化還原起始方式合成。接下來將PEDOT:PSS與PNN在水中混合成PDPNN均勻溶液備用。其中PEDOT:PSS在複合材料中的含量調配為0到20 wt%。溫度敏感性與導電性複合材料(TCC)薄膜與靜電紡絲纖維膜可以分別用迴旋塗佈法和靜電紡絲製成。在經過熱交聯之後,可製成穩定的PDPNN的薄膜與靜電紡絲纖維膜。就導電能力上而言,PDPNN薄膜的電導度是優於靜電紡絲纖維膜的。兩者在都在PEDOT:PSS含量高於12 wt%後,電導度大幅提升。在溶脹比率的表現上,靜電紡絲纖維膜的吸水能力較薄膜為佳。在溫感性上可利用DSC來觀察它們的相行為。PNN在交聯後,溫感性依然保持,但吸熱峰有變寬的趨勢。引入PEDOT:PSS則會逐漸地使溫感性下降。溫感的導電特性可以經由量測在25到50 ºC水浴溫度下TCC薄膜與纖維膜的表面電阻值來進行研究。隨著溫度的上升,複合材料靜電紡絲膜的結構會逐漸緊縮,此時表面電阻值會逐漸下降。TCC靜電紡絲纖維膜的敏感度是高於TCC薄膜的,因為TCC纖維膜有較佳的吸水能力。因具有高孔隙度和快速反應速率等特性,TCC可以運用在微型感應器的領域。 在第五章描述如何成功製備具有鞘/芯結構之溫感性與導電性的高分子複合材料靜電紡絲纖維膜。熱交聯型共聚物poly(N-isopropylacrylamide-co-N-methylol acrylamide) (PNN)可以利用氧化還原起始方式合成。接下來將PEDOT:PSS與PNN在水中混合成PDPNN均勻溶液以作為鞘之電紡溶液,而PNN水溶液則作為芯之電紡溶液。再利用同軸靜電紡絲技術可製備出芯鞘型電紡絲。然後利用熱交聯和掺雜(doping)的程序製成溫感性導電性靜電紡絲膜(TCC fiber mat)。利用SEM與TEM觀測鞘芯型靜電紡絲的結構,可觀察到表面平滑之鞘芯結構電紡絲。複合材料電紡絲之溫感性可利用DSC和溶脹比量測,結果呈現此複合材料靜電紡絲具有良好的溫感性。此外,我們也研究了複合材料電紡絲膜之導電性質與其表面電阻值隨溫度的變化。 在附錄中,我們利用熱力學的方式去探討PNIPAAm系列之混合水溶液的相變化行為。Fe3O4奈米顆粒是經由共沉澱法製作。再經由月桂酸改質表面之後,可以得到分散性佳的雙層月桂酸改質Fe3O4奈米顆粒(DLF)。PNIPAAm、Fe3O4/PNIPAAm與DLF/PNIPAAm複合材料之熱性質與溫度敏感性質是用DSC量測。我們利用DSC量測出相變化時焓與熵的變化量(△H、△S)及LCST。將Fe3O4/PNIPAAm與DLF/PNIPAAm和PNIPAAm做比較,△H 與△S皆因添加物(Fe3O4、DLF)而下降。而LCST會受到DLF的影響而逐漸下降。 The objective of this study is to fabricate stable thermo-responsive polymer composite and their electrospun fibers. This work can be divided into two parts. The first part includes chapter 2 and chapter 3, which are about preparation and characterization of magnetic and thermo-responsive composites, Fe3O4/PNIPAAm, and their electrospun fibers. The second part includes chapter 4 and chapter 5, which is about conductive and thermo-responsive composites, PEDOT:PSS/PNIPAAm, and their electrospun fibers. On the other hand, thermo-responsive conductive sheath/core fiber mats prepared by co-axial electrospinning were also prepared and studied. In chapter 2, thermo-responsive magnetic polymer composites and nanofibers were fabricated. Their thermal and magnetic properties were also investigated. Fe3O4 nanoparticles were prepared by coprecipitation method. Further condensation reaction was used to fabricate the double-layer lauric acid modified Fe3O4 (DLF) nanoparticles dispersed well in water. Thermal properties of poly(N-isopropylacrylamide) (PNIPAAm) and DLF/PNIPAAm composites and their aqueous solutions were measured by TGA and DSC. With the increasing of DLF content, the interaction between DLF and PNIPAAm caused the LCST of polymer solution to shift from 33 to 31.25 ºC. The effects of concentration and pH on LCST were also studied. The DLF/PNIPAAm nanofibers were fabricated by electrospinning. Their diameters were around 100 to 250 nm. Magnetization curves of DLF/PNIPAAm composite and nanofibers were overlapped and the saturated magnetizations were the same. Magnetic attraction behaviors of DLF/PNIPAAm polymer solution at temperatures below and above LCST were different. Aggregation of DLF/PNIPAAm above LCST enhanced magnetic moment density as well as magnetic attraction ability. In chapter 3, UV-Crosslinked magnetic thermo-responsive composite (MTC) fiber mats were fabricated by electrospinning process successfully. Thermo-responsive PNIPAAm and magnetic Fe3O4 were synthesized by redox-initiation polymerization and coprecipitation, respectively. To provide crosslinking ability of MTC fibers, the crosslinking agent (DPHA) and photo-initiator were mixed with PNIPAAm and Fe3O4 in the ethanol as the electrospinning solutions. After electrospinning and UV-curing process, MTC fiber mats were obtained. Thermo-responsivity of composite fibers was measured by DSC and swelling ratio test. The composite fiber mats showed better water absorption ability and thermo-responsivity than films owing to fibrous structure. Morphology of composite fibers was observed by SEM and TEM. The magnetic property of MTC fiber mats was measured by SQUID. The saturated magnetization was proportional to Fe3O4 amount in the fiber mats. The thermo-dependent magnetic behavior of MTC fiber pieces in water was observed under various magnetic fields at the temperatures below and above LCST. The shrinking MTC fiber pieces in water showed better magnetic attraction ability. In Vitamin B12 releasing measurement at 25 and 37 ºC, drug-loaded fiber carriers exhibited burst releasing at 37 ºC and gradual diffusion at 25 ºC. With the hyperthermia treatment, MTC fiber carrier released drug faster owing to its thermo-responsive phase transition. In chapter 4, the thermo-responsive conductive polymer composite thin film and fiber mat whose electrical property is dependent on temperature were fabricated successfully. The thermo-crosslinkable and thermo-responsive copolymer, poly(N-isopropylacrylamide-co-N-methylol acrylamide) (PNN), were synthesized by redox initiation polymerization. By mixing PNN and PEDOT:PSS in water, the PDPNN solutions were prepared for further processing. The PEDOT:PSS content in the composite were from 0 to 20 wt%. The thermo-responsive conductive composite (TCC) thin film and fiber mat were fabricated by spin-coating and electrospinning process of PDPNN solutions respectively. After thermo-crosslink process, the PDPNN thin films and fiber mats were prepared. The conductivity of PDPNN thin film was better than that of fiber mat. The conductivity of TCCs were dramatically increasing when PEDOT:PSS content was increased over 12 wt%. The swelling of PDPNN fiber mats were higher than that of thin films owing to high porosity of fibrous structure. The phase behavior of TCCs in water was studied using DSC. The thermo-responsivity of PNN films and fiber mats was retained and the endothermic peak was widening after crosslinking. Incorporation of PEDOT:PSS in the composite gradually decreased thermo-responsivity. The thermo-responsive conductive property was measured by measuring surface resistivity of TCCs in the water bath at the temperature from 20 to 50 ºC. With the increasing of temperature, the TCCs shrinked to dense structure and showed lower surface resistivity. The TCC fibers mat exhibited more sensitive to temperature than thin films owing to high swelling ability of fibrous structure. The TCCs could be applied in the micorsensor field owing to the high porosity and rapid response time. In chapter 5, the thermo-responsive conductive composite (TCC) fiber mats with sheath/core structure were fabricated successfully. The thermo-crosslinkable and thermo-responsive copolymer, poly(N-isopropylacrylamide-co-N-methylol acrylamide) (PNN), was synthesized by redox initiation polymerization. By mixing PNN and PEDOT:PSS in water, the PDPNN solutions were prepared for sheath solution. PNN aqueous solution was prepared as core solution. Then sheath/core fibers composed by PDPNN/PNN were fabricated by co-axial electrospinning. After thermo-crosslinking and doping by DMSO, the sheath/core fiber mats with different compositions were obtained. Morphological analysis of sheath/core fiber mats were observed by SEM and TEM. Smooth fibers with sheath/core structure were obtained. The phase behavior of TCC fiber mats was studied using DSC. Swelling ratios of them under various temperatures were also studied. Both tests showed thermo-responsivity of TCC fiber mats. The electrical properties of TCC fiber mats were measured. The thermo-responsive conductive property was studied by measuring surface resistance of TCC fiber mats in the water with various temperatures from 25 to 50 ºC. With increasing of temperature, the TCC fiber mats shrank to dense structure and showed lower surface resistance. The TCC fibers mat exhibited sensitive to temperature and could be used as thermo-sensor applications. In the appendix, PNIPAAm-based composite solutions were prepared and studied in a thermodynamic way. Fe3O4 nanoparticles were prepared by coprecipitation method. Further condensation reaction was used to fabricate the double-layer lauric acid modified Fe3O4 (DLF) nanoparticles dispersed well in water. Thermal properties of poly(N-isopropylacrylamide) (PNIPAAm), Fe3O4/PNIPAAm and DLF/PNIPAAm composite solutions were measured by DSC. The enthalpy change, entropy change and LCST during phase transition were obtained by curves of DSC. Comparing Fe3O4/PNIPAAm and DLF/PNIPAAm with PNIPAAm solution, △H and △S decreased owing to the effect of additives (Fe3O4 and DLF). The LCST of DLF/PNIPAAm solution decreased gradually with increasing of DLF content. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/53780 |
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顯示於系所單位: | 高分子科學與工程學研究所 |
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