VAPOR GROWN CARBON FIBERS FOR BIOMEDICAL APPLICATIONS

气相生长碳纤维联合收割机结合了高强度、高强度和高强度的理想特性， 导热性和导电性，高强度重量比，非 灾难性的破坏模式，高模量，显著的各向异性和化学 阻力 它们是一种相对较新的石墨纤维， 在增强复合材料中的应用前景广阔， 假体装置和作为微电极用于监测细胞过程。 电子传导的固有各向异性表明其 在神经科学中的应用。 这项研究的目标是调整或“微调”的电气和 导热系数、拉伸强度和模量以及表面 通过各种掺杂、涂覆和退火程序， 允许它们应用于假体和作为微电极， 适合生物学的电信号传输和神经模型。 我们 将试图完善气相生长纤维的环形结构， 一个“封闭”，缺乏积极的表面边缘。 “关闭”是必要的， 人体中需要化学惰性的那些应用。 这 由石墨的001平面的低反应性提供。 这 “封闭”还通过呈现非常高的抗氧化性来增强抗氧化性。 低反应边表面积。 我们建议通过等离子体涂覆纤维 沉积金刚石以降低孔隙率并增加物理性能 纤维的强度。 或者，表面粗糙度将是 当生长成肌腱和肌肉纤维时， 需要的话 这一过程将通过控制氧化进行。 通过使用固态ESR测量，在我们新的 发展理论治疗，我们将表征气相生长碳 生物应用的纤维。 的极其重要的性质 电子迁移率，电导率各向异性，晶粒尺寸， 基面排序，和电子扩散常数将推导出从 ESR吸收线形分析。 电子显微镜会发现 由于生长条件的变化和那些 伴随着热退火。 测量总表面积， 氪和活性表面积与氧气将进行。 氧 表面浓度将通过监测Ols和Cls XPS确定 强度 用低能电子探测表面有序性 衍射法 这些纤维作为微电极的效用将是 与格雷格·斯温博士合作研究， 堪萨斯大学的生物分析研究。 气相生长纤维的所有上述性质取决于 关键在于它们的热制备和化学制备方法。 新 将采用生长方法来增强纤维的 有用性 因此，我们将确定最佳的制备方法， 加工条件，这将导致先进的修复材料， 神经和生化用途。

Vapor-grown carbon fibers combine the desirable characteristics of high thermal and electrical conductivity, high strength to weight ratio, non- catastrophic failure modes, high modulus, marked anisotropy and chemical resistance. They are a relatively new form of graphite fiber which hold great promise for application in reinforced composite materials for prosthetic devices and as microelectrodes for monitoring cell processes. The inherent anisotropy of the electronic conduction suggests their application in the neural sciences. The goal of this research is to tailor or "fine-tune" the electrical and thermal conductivity, the tensile strength and the modulus and the surface properties through various doping, coating and annealing procedures to allow for their application in prosthesis and as microelectrodes and biologically-suited electrical signal transmission and nerve models. We will attempt to perfect the annular structure of vapor-grown fibers to give a "closure", the lack of active surface edges. "Closure" is necessary for those applications in the human body that require chemical inertness. This is provided by the low reactivity of the 001 planes of graphite. This "closure" also enhances the resistance to oxidation by presenting a very low reactive-edge surface area. We propose to coat fibers via plasma deposition with diamond to lower porosity and increase the physical strength of the fibers. Alternatively, surface roughness will be incorporated into the fibers when growth into tendons and muscle fibers is desired. This process will be carried out through controlled oxidation. Through the use of solid-state ESR measurements, guided by our newly developed theoretical treatment, we will characterize vapor-grown carbon fibers for biological applications. The extremely important properties of electron mobility, conductivity anisotropy, crystallite size, degree of basal plane ordering,a nd electron diffusion constant will be inferred from analysis of ESR absorption lineshapes. Electron microscopy will reveal structural modifications due to changes in growth conditions and those accompanying thermal annealing. Measurement of total surface area with krypton and active surface area with oxygen will be performed. Oxygen surface concentration will be determined by monitoring the Ols and Cls XPS intensities. Surface order will be probed with low-energy electron diffraction. The utility of these fibers as microelectrodes will be studied in collaboration with Dr. Greg Swain at the Center for Bioanalytical Research at the University of Kansas. All of the above-mentioned properties of vapor-grown fibers depend critically upon the method of their thermal and chemical preparation. New growth methods will be employed in an effort to enhance the fibers' usefulness. We will, thus, determine the optimal preparation and processing conditions which will lead to advanced materials for prothesis, neural and biochemical use.