Polymeric nanofibers: isodiametric design space and methodology for depositing aligned nanofiber arrays in single and multiple layers
Polymeric nanofibers: isodiametric design space and methodology for depositing aligned nanofiber arrays in single and multiple layers
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DOI：
10.1038/pj.2013.1
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发表时间：
2013-07-01
期刊：
影响因子：
2.8
通讯作者：
Wang, Ji
中科院分区：
文献类型：
--
作者：
Nain, Amrinder S.;Wang, Ji
引言聚合物微/纳米纤维由于其在组织工程、智能纺织品、传感器和执行器等不同领域的广泛应用而变得越来越重要。传统上，成熟的纺粘技术、1、2熔喷、3、4干纺、5、6共轭纺丝7和CO2激光细化8可生产直径为微米级、长度超过一米的聚合物纤维。然而，由于聚合物材料的脆弱性，纳米级直径的长纤维的定向沉积和连续生产一直是一个挑战。此外，许多应用需要以用户定义的几何间距排列配置沉积光滑、均匀和无缺陷的纳米纤维阵列。目前已开发出多种工艺来制造聚合物纳米纤维阵列，包括静电纺丝、9-13 模板合成、14、15 相分离、16、17 和顺序微干纺丝。 18 在所有这些方法中，静电纺丝可能是最流行的工艺，它可以连续生产直径从几十纳米到几微米的纤维，并且需要专门的策略来对齐沉积这些纤维。 19-24 尽管纳米纤维基本上可以单层和多层排列，但对纤维直径和间距的严格控制尚未实现。当前最先进的制造方法的缺陷继续阻碍聚合物纳米纤维应用的改进。在这里，我们提出了一种基于我们之前报道的 STEP（基于喷丝头的可调工程参数）技术 25 的非静电纺丝策略，以沉积直径范围从亚 100 纳米到微米、长度至少为几毫米的均匀聚合物纤维阵列。此外，该策略还能够控制相邻光纤之间的间距。纤维直径的控制是通过操纵聚合物溶剂溶液中的聚合物链缠结来实现的，这与聚合物溶液的浓度和分子量直接相关。映射分子缠结-纤维直径关系以获得等径设计空间，这为估计纤维直径提供了方便的视觉工具。此外，使用等径纤维作为构建块演示了单层和多层纳米纤维组件，这有助于建立一个急需的、稳健的工程框架，用于在分层组件中沉积对齐的微/纳米纤维。
INTRODUCTION Polymeric micro/nanofibers are increasingly gaining importance due to their versatile applications in diverse fields, such as tissue engineering, smart textiles, sensors and actuators. Traditionally, the well-established techniques of spun bounding, 1, 2 melt blowing, 3, 4 dry spinning, 5, 6 conjugate spinning 7 and CO2 laser thinning 8 produce polymeric fibers with diameters on the micron scale and lengths in excess of a meter. However, aligned deposition and continuous production of long fibers with nanoscale diameters has been a challenge due to the fragility of polymeric materials. In addition, numerous applications require the deposition of smooth, uniform and defect-free nanofiber arrays in aligned configurations with user-defined geometrical spacing. Several processes have been developed to fabricate polymer nanofiber arrays, including electrospinning, 9–13 template synthesis, 14, 15 phase separation 16, 17 and sequential micro dry spinning. 18 Of all these methods, electrospinning is perhaps the most popular process, allowing for the continuous production of fibers ranging from tens of nanometers to a few microns in diameter and requiring specialized strategies for the aligned deposition of these fibers. 19–24 Although nanofibers can be essentially aligned in single and multiple layers, tight control over the fiber diameter and spacing has yet to be realized. The deficiencies of the current state-of-the-art fabrication methods continue to hinder improvements in the applications of polymer nanofibers. Here, we present a non-electrospinning strategy based on our previously reported STEP (Spinneret based Tunable Engineered Parameters) technique 25 to deposit arrays of polymer fibers with uniform diameters ranging from sub-100nm to microns and lengths of at least several millimeters. In addition, this strategy has the ability to control adjacent fiber–fiber spacing. The control of fiber diameter is achieved by manipulating the polymer chain entanglements in the polymer–solvent solution, which are directly related to the polymer solution concentration and the molecular weight. The molecular entanglement–fiber diameter relationships are mapped to obtain an isodiametric design space, which provides a convenient visual tool for estimating the fiber diameters. Furthermore, nanofiber assemblies in single and multiple layers are demonstrated using isodiametric fibers as building blocks, which helps to establish a much needed, robust engineering framework for depositing aligned micro/nanofibers in hierarchical assemblies.