X-ray photoelectron emission microscopy and time-of-flight secondary ion mass spectrometry analysis of ultrathin fluoropolymer coatings for stent applications.
X-ray photoelectron emission microscopy and time-of-flight secondary ion mass spectrometry analysis of ultrathin fluoropolymer coatings for stent applications.
复制标题
对支架应用的超薄含氟聚合物涂层进行 X 射线光电子发射显微镜和飞行时间二次离子质谱分析。
作者：
P. Hale;S. Turgeon;Paula Horny;François Lewis;N. Brack;Grant van Riessen;P. Pigram;D. Mantovani
含氟聚合物等离子体涂层因其化学稳定性、顺应性和疏水性而被用作支架涂层。挑战在于这些涂层在体内支架扩张后保持附着、稳定和粘合的能力，这可能会产生高达25%的局部塑性变形。通过多步工艺在316L不锈钢上制备了等离子体涂层样品，并对一些涂层样品进行了塑性变形以模拟支架的膨胀。然后通过X射线光电子能谱(XPS)、X射线光电子发射显微镜(X-PEEM)和飞行时间二次离子质谱仪(TOF-SIMS)进行分析，以确定这种变形对涂层和界面区域的化学和物理影响。虽然XPS分析始终表明涂层是连续的，没有明显的变形影响，但TOF-SIMS和近边X射线吸收精细结构(来自X-PEEM)数据表明，所有涂层中都存在一定密度的孔洞和针孔，变形的涂层中存在稀疏的裂缝和分子碎片。受缺陷影响的面积分数之小和化学变化的微妙，只能通过后一种技术的较高化学灵敏度来证明。
Fluoropolymer plasma coatings have been investigated for application as stent coatings due to their chemical stability, conformability, and hydrophobic properties. The challenge resides in the capacity for these coatings to remain adherent, stable, and cohesive after the in vivo stent expansion, which can generate local plastic deformation of up to 25%. Plasma-coated samples have been prepared by a multistep process on 316L stainless steel substrates, and some coated samples were plastically deformed to mimic a stent expansion. Analyses were then performed by X-ray photoelectron spectroscopy (XPS), X-ray photoelectron emission microscopy (X-PEEM), and time-of-flight secondary ion mass spectrometry (TOF-SIMS) to determine the chemical and physical effects of such a deformation on both the coating and the interfacial region. While XPS analyses always showed a continuous coating with no significant effect of the deformation, TOF-SIMS and near-edge X-ray absorption fine structure (derived from X-PEEM) data indicated the presence of a certain density of porosity and pinholes in all coatings as well as sparse fissures and molecular fragmentation in the deformed ones. The smallness of the area fraction affected by the defects and the subtlety of the chemical changes could only be evidenced through the higher chemical sensitivity of these latter techniques.