Plasma polymer chemical gradients for evaluation of surface reactivity: epoxide reaction with carboxylic acid surface groups
Plasma polymer chemical gradients for evaluation of surface reactivity: epoxide reaction with carboxylic acid surface groups
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DOI：
10.1039/b311256j
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发表时间：
2004-01-01
影响因子：
--
通讯作者：
Short, RD
中科院分区：
文献类型：
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作者：
Alexander, MR;Whittle, JD;Short, RD
可以使用等离子体聚合来制造特定化学的有机表面。最近开发的沉积方法允许在表面羧基浓度梯度制造超过13毫米的距离从混合的丙烯酸/octylene等离子体。使用卤素取代的环氧化物分子的挥发性物质的化学吸附，使用小面积XPS分析的调查中，这些表面的效用已被证明。自动化小面积XPS分析和化学梯度的组合已被用来减少所需的样品数量的一个因素的20相比，传统上采用的一个数据点，一个样品的方法。我们相信，化学梯度是一个灵活的和广泛适用的路线，以减少样品制备负荷，在这样的研究吸附物表面的反应性。环氧官能团与表面的反应性在粘合科学领域非常重要;大多数高性能涂料和粘合剂都是基于环氧树脂。在此，确定了环氧化物化学吸附量与羧酸浓度之间的相互关系。很明显，化学吸附的水平强烈依赖于羧基浓度，表现出阈值表面组成，低于该阈值没有观察到反应。卤素标记原子的影响是明确的，它表明，氟标记的环氧化物具有增强的反应性相比，氯或溴取代的环氧化物。还观察到，发生表氟醇分子的降解以在等离子体聚合物表面形成无机氟物质。
Organic surfaces of specific chemistry can be fabricated using plasma polymerisation. A recently developed deposition approach allows gradients in surface carboxyl group concentration to be fabricated over a distance of 13 mm from a mixed acrylic acid/octadiene plasma. The utility of these surfaces in the investigation of the chemisorption of volatile specie using small area XPS analysis has been demonstrated using halogen-substituted epoxide molecules. The combination of automated small area XPS analysis and chemical gradients has been used to reduce the number of samples required by a factor of 20 compared with the traditionally employed one data point-one sample approach. We believe that chemical gradients are a flexible and widely applicable route to reducing the sample preparation load in such a study of adsorbate - surface reactivity. The reactivity of epoxy functionalities with surfaces is of great importance in the field of adhesion science; most high performance paints and adhesives are based on epoxy resins. Here, the inter-relationship between the amount of epoxide chemisorption and the carboxylic acid concentration is determined. It is apparent that the level of chemisorption is strongly dependent on the carboxyl concentration, exhibiting a threshold surface composition below which reaction was not observed. The influence of the halogen tag atom is made clear; it is shown that a fluorine tagged epoxide has enhanced reactivity compared to chlorine or bromine substituted epoxides. It is also observed that degradation of the epifluorohydrin molecule occurs to form an inorganic fluorine species at the plasma polymer surface.