肌腱仿生用定向PLLA微纳米纤维的静电纺丝工艺参数研究

采用左旋聚乳酸(PLLA)为基材研究静电纺丝工艺过程对聚乳酸纤维形貌和性能的影响,主要包括环境湿度、纺丝溶液浓度、接收转速、收集距离、注射泵推注速度、附加电压等过程参数。结果表明,接收转速与纺丝液浓度分别是影响纤维定向排列程度和纤维直径的最主要因素,其次是接收距离、环境湿度、推注速度。当聚乳酸-氯仿溶液聚合物质量浓度为80 mg/mL、纺丝电压为25 kV、接收距离为20 cm、注射泵推注速度为0.3 μL/s以及接收转速为1500 r/min时,纤维取向性良好,平均直径为(0.94±0.21) μm,可达到模拟肌腱组织天然细胞外基质结构的要求。     

电纺丝法制备聚环氧乙烯超细纤维

采用静电纺丝的方法制备出聚环氧乙烯超细纤维。通过场发射环境扫描电子显微镜(ESEM)对超细纤维的形貌及直径分布进行了表征。研究了纺丝过程中溶液浓度、不同溶剂和射流长度三个参数对纤维形态的影响。研究结果表明,水溶液的浓度对得到连续的超细纤维起决定性作用。在电纺丝的工艺参数中,混合溶液的性质对纤维的形态和直径分布影响很大;对于不同的溶液体系也要采取不同的射流长度。     

静电纺丝参数对聚乙酸乙烯酯纤维形貌的影响

以N,N-二甲基甲酰胺(DMF)为溶剂,采用静电纺丝法制备了聚乙酸乙烯酯(PVAc)纤维.用场发射扫描电镜观察了PVAc纤维的形貌,研究了PVAc溶液质量分数、纺丝电压、收集距离等对纤维形貌及平均直径的影响.研究结果表明,PVAc溶液质量分数和纺丝电压对纤维的形貌有显著影响,随着PVAc溶液质量分数和纺丝电压的增大,纤维的平均直径增大;收集距离对纤维形貌的影响较小.尝试采用静电纺丝法制备了炭黑和PVAc的复合纤维,以增强纤维的导电性,成为导电碳纤维,但炭黑会显著降低PVAc的成纤性,因为它会吸附溶剂DMF,使溶剂在电纺过程中不易挥发,射流不能固化成纤维.     

聚乳酸的静电纺丝行为及其纤维结构研究

用静电纺丝法制备了纤维平均直径为350～1900nm的聚乳酸纤维,用扫描电镜研究了纤维的形貌,并用实验设计方法研究了纺丝工艺参数(溶液浓度、电场电压)对纤维平均直径的影响,同时用差示扫描量热分析和X射线衍射研究了静电纺丝所得纤维的结构.研究结果表明:溶液浓度对纤维的平均直径有较大的影响,溶液浓度较低时易形成珠状结构的纤维,纤维的平均直径随着聚合物浓度的增大而增大,并随电场电压的增大而减小.与浇铸膜相比,静电纺丝所制得的纤维有较低的结晶度,并且结晶结构不够完善.由静电纺丝制备的聚乳酸纳米纤维膜在组织工程和药物缓释等领域有潜在的应用前景.     

壳聚糖/聚氧乙烯复合纺丝液性能对静电纺丝的影响

为了研究壳聚糖/聚氧乙烯复合纺丝液性能对静电纺丝的影响,利用质量分数为3％的壳聚糖(CS)与聚氧乙烯(PEO)以不同的质量比溶解在浓度为50％的冰乙酸水溶液中制备了CS/PEO复合纺丝液,采用静电纺丝技术制备了CS/PEO复合纳米纤维.用扫描电子显微镜(SEM)对制备出的CS/PEO复合纳米纤维进行表征,并测试了CS/PEO复合纺丝液的溶液性能.从复合纺丝液性能对静电纺纤维成型的影响机理角度对实验结果进行了分析.分析结果表明,在其他静电纺丝参数一定时,纺丝液黏度影响射流的稳定性,从而影响纤维的形貌和直径.只要纺丝液电导率在合适的范围内,对静电纺的影响不大.从泰勒的临界公式中得出了纺丝液临界电压与纺丝液表面张力最佳值的一一对应关系,并与本实验中的实验数据相吻合.     

超声波振动静电纺丝行为研究

为了提高高浓度聚丙烯腈(PAN)溶液的静电可纺性,引进超声波振动技术处理溶液,并对振动处理后的溶液进行静电纺丝。通过高速摄像技术对其静电纺丝行为研究,观察振动功率对射流形态,包括泰勒锥、包络角和纤维沉积面积的影响规律。通过扫描电子显微镜(SEM)观察,进一步验证了超声波振动对聚合物溶液的静电可纺性的影响。并通过线性拟合,推导出沉积面积与纤维直径的函数方程。结果表明:超声波振动处理后,高浓度PAN溶液静电纺射流鞭动幅度加大,纤维直径降低,溶液的静电可纺性提高,可纺质量分数增大。     

静电纺丝纤维形貌的研究

综述了溶液粘度、电荷密度等因素对静电纺丝纤维形貌的影响.在静电纺丝过程中,溶液粘度与电荷密度是影响纤维形貌的主要因素,它们具有协同作用.同时,这两个因素本身也受溶液浓度、聚合物分子量、溶液电导率等因素的影响,因而在纺丝时需综合考虑以上因素以获得形貌完善的纤维.     

静电纺羧甲基壳聚糖纳米纤维直径的预测模型

目的研究羧甲基壳聚糖溶液浓度和静电纺丝工艺参数对纳米纤维直径的影响。方法按照静电纺丝的原理,选取溶液浓度、电压、流量和喷头直径等4个影响因素,使用响应面法中的Box-Behnken设计对羧甲基壳聚糖静电纺丝纤维直径进行预测,得到二次多元回归模型。结果羧甲基壳聚糖溶液浓度、流量、浓度的二次项和喷头直径的二次项对纤维直径影响显著,该模型实验值与预测值高度拟合。结论通过响应面得到的模型能预测羧甲基壳聚糖纤维的直径,同时明确了羧甲基壳聚糖纤维的最佳电纺参数。     

静电纺丝法制备高分子量聚左旋乳酸纳米纤维及其表征

利用静电纺丝法制备了高分子量聚左旋乳酸(PLLA)纳米纤维,研究了溶液浓度、纺丝距离和纺丝电压对纤维形貌的影响.用扫描电子显微镜(SEM)对纤维形貌进行了表征,结果表明,当PLLA溶液浓度为3%,纺丝距离为20.5cm,纺丝电压为13kV时得到的纤维形貌较好.再用差示扫描量热法(DSC)对纤维的热学性能进行了表征,用X...     

磁场辅助静电纺有序PAN/PVP复合纳米纤维的制备及工艺优化

磁场辅助静电纺丝(MFAES)技术能够制备有序纳米纤维,但其参数间的匹配关系很少被系统研究。通过MFAES方法制备了有序聚丙烯腈(PAN)/聚乙烯吡咯烷酮(PVP)复合纤维,应用正交实验分析了纺丝中主要的过程参数对复合纤维直径和有序度的影响。实验表明:随着浓度增大,复合纤维的直径增大,得到复合纤维的最小直径为496nm;溶液浓度和纺丝电压是复合纤维有序度的显著影响因素,在溶液浓度为14wt%、PAN/PVP配比为80∶20、纺丝电压为12kV、磁铁间距为2cm时,复合纤维的有序度最高达95%。     

Polyacrylonitrile nanofibers prepared using coaxial electrospinning with LiCl solution as sheath fluid

A modified coaxial electrospinning process including an electrolyte solution as sheath fluid was used for preparing high quality polymer nanofibers. A series of polyacrylonitrile (PAN) nanofibers were fabricated utilizing a coaxial electrospinning containing LiCl in N, N-dimethylacetamide (DMAc) as the sheath fluid. FESEM results demonstrated that the sheath LiCl solutions have a significant influence on the quality of PAN nanofibers. Nanofibers with smaller diameters, smoother surfaces and uniform structures were successfully prepared. The diameters of nanofibers were controlled by adjusting the conductivity of the sheath fluid over a suitable range and this was determined by varying LiCl concentrations. The influence of the effect of LiCl on the formation of PAN fibers is discussed and it is concluded that coaxial electrospinning with electrolyte solutions is a convenient and facile process for achieving high quality polymer nanofibers.     

Edge electrospinning for high throughput production of quality nanofibers

A novel, simple geometry for high throughput electrospinning from a bowl edge is presented that utilizes a vessel filled with a polymer solution and a concentric cylindrical collector. Successful fiber formation is presented for two different polymer systems with differing solution viscosity and solvent volatility. The process of jet initiation, resultant fiber morphology and fiber production rate are discussed for this unconfined feed approach. Under high voltage initiation, the jets spontaneously form directly on the fluid surface and rearrange along the circumference of the bowl to provide approximately equal spacing between spinning sites. Nanofibers currently produced from bowl electrospinning are identical in quality to those fabricated by traditional needle electrospinning (TNE) with a demonstrated ～ 40 times increase in the production rate for a single batch of solution due primarily to the presence of many simultaneous jets. In the bowl electrospinning geometry, the electric field pattern and subsequent effective feed rate are very similar to those parameters found under optimized TNE experiments. Consequently, the electrospinning process per jet is directly analogous to that in TNE and thereby results in the same quality of nanofibers.     

Electrospinning of nanofibers: Characterization of jet dynamics and humidity effects

Electrospinning is a method to produce submicron polymer fibers for a wide range of applications. In many applications, the average electrospun fiber size and uniformity are important for the product's performance and process economics. Thus, it is desirable for electrospinning to achieve consistent and controllable fiber diameters. However, the current state-of-the-art electrospinning process can result in variable fiber diameters, both run-to-run and during a run. This paper investigates how the operating regime as well as several important process factors affect fiber diameter using a vision-based system. For aqueous polyethylene oxide (PEO) solutions, it is found that the relative humidity has a strong effect on fiber diameter. Correlations between measurable parameters and fiber diameter are also developed to provide the ability to achieve the desired fiber diameters. The jet dynamics are experimentally identified through step response for development of appropriate control strategies.     

The effect of relative humidity and evaporation rate on electrospinning: fiber diameter and measurement for control implications

This paper presents an experimental study of the influence that relative humidity and evaporation rate have on the electrospinning process in terms of fiber diameter, process measurements, and selection of operating regime (applied voltage and flow rate) for polyethylene oxide/water (aqueous) solutions and poly(vinylpyrrolidone)/alcohol (non-aqueous) solutions. Poly(vinylpyrrolidone) alcohol solutions are studied to understand the separate influence of relative humidity and evaporation rate. Correlations are developed that relate measurable process parameters (jet diameter, charge density) as well as relative humidity and evaporation rate to fiber diameter. In addition, the influence that relative humidity has on selection of operating regime to achieve desired fiber diameter and maximum production rate is presented.     

PVP nanofibers prepared using co-axial electrospinning with salt solution as sheath fluid

A modified co-axial electrospinning process using salt solutions as sheath fluids for preparing polymer nanofibers was investigated. A series of polyvinylpyrrolidone (PVP) fibers were prepared with NaCl aqueous solutions at varying concentrations as sheath fluids. The sheath fluid had a significant influence on the formation of the compound Taylor cone. Scanning electron microscopy results demonstrated that the diameters of PVP nanofibers could be manipulated through the concentration of NaCl solutions within an appropriate range. With 2 mg ml^− 1 NaCl solution as sheath fluid, the smallest PVP nanofibers, with a diameter of 120 ± 40 nm, were obtained. Co-axial electrospinning with salt solutions as sheath fluids is a facile method for achieving finer, homogeneous polymer nanofibers.     

Effect of the relative humidity on the fibre morphology of polyamide 4.6 and polyamide 6.9 nanofibres

To obtain uniform and reproducible nanofibres, it is important to understand the effect of the different electrospinning parameters on the nanofibre morphology. Even though a lot of literature is available on the electrospinning of nanofibres, only minor research has been performed on the effect of the relative humidity (RH). This paper investigates the influence of this parameter on the electrospinning process and fibre morphology of the hydrophilic polyamide 4.6 and the less hydrophilic polyamide 6.9. First, the electrospinning process and deposition area of the nanofibres is examined at 10, 50 and 70 % RH. Subsequently, the effect of the polyamide concentration and solvent ratio on the fibre morphology is investigated using scanning electron microscopy and differential scanning calorimetry. It was found that the nanofibre diameter decreased with increasing RH. This resulted in less stable crystals for polyamide 4.6 while electrospinning of polyamide 6.9 at higher RH led to slightly more stable crystals. In conclusion, the water affinity of a polymer is an important factor in predicting the nanofibre morphology at different humidities.     

电纺丝制备纳米纤维及其应用

电纺丝技术是利用高压静电将聚合物或具有粘弹性的溶液制备成纳米级直径纤维的一种加工技术。电纺丝纤维膜由于其高比表面积、良好的生物仿生性能,在生物组织工程支架、药物载释、伤口修复等方面有较高的应用价值。近年来,大量文献报道,通过对电纺丝装置以及纺丝过程参数的改进和优化,制备出功能化和具有特殊结构的纳米纤维材料。本文从电纺丝装置的改进、纺丝过程优化等方面简述了电纺丝技术的进展。概述了电纺丝法制备特殊结构的纳米纤维的方法,及其在生物组织工程、药物载释等方面的应用。     

Controlled continuous patterning of polymeric nanofibers on three-dimensional substrates using low-voltage near-field electrospinning

We report on a continuous method for controlled electrospinning of polymeric nanofibers on two-dimensional (2D) and three dimensional (3D) substrates using low voltage near-field electrospinning (LV NFES). The method overcomes some of the drawbacks in more conventional near-field electrospinning by using a superelastic polymer ink formulation. The viscoelastic nature of our polymer ink enables continuous electrospinning at a very low voltage of 200 V, almost an order of magnitude lower than conventional NFES, thereby reducing bending instabilities and increasing control of the resulting polymer jet. In one application, polymeric nanofibers are freely suspended between microstructures of 3D carbon on Si substrates to illustrate wiring together 3D components in any desired pattern.     

电纺丝技术--一种高效低耗的纳米纤维制备方法

电纺丝技术是一种高效低耗的纳米纤维制备方法。电纺丝技术的基本装置由高压直流电源、带有细小喷丝头的样品管和收集板三部分组成。描述了使用该技术将高分子制备成纳米纤维的基本原理。对11种处于发展和完善中的电纺丝装置进行了简要介绍。