CeNIDE - Center for Nanointegration Duisburg-Essen, 47057 Duisburg, Germany.
Langmuir. 2009 Oct 20;25(20):12393-8. doi: 10.1021/la901718k.
Nonlinear laser processing of silane-based monolayers is used to fabricate nanostructured chemical templates for the selective growth of polymer brushes in confined domains via surface-initiated polymerization (SIP). Upon varying the laser parameters, reactive domains with lateral dimensions from several micrometers down to the sub-100-nm range are fabricated. This provides a versatile means for studying the morphological scaling behavior of confined polymer brushes. Here, the surface-initiated growth of a stimuli-responsive polymer, poly(N-isopropylacrylamide) (PNiPAAm), via atom transfer radical polymerization (ATRP) is investigated. Polymer chains at the domain boundaries extend into the surrounding polymer-free areas. For this reason the width of confined polymer brushes is significantly larger than that of the underlying domains. Within experimental error, though, the excess width does not depend on the domain size. In contrast, the brush height decreases more and more when the domain size falls below a certain value. Simple considerations point to a geometrical scaling relation between height and width of the polymer brushes. These results are considered as essential for implementation of SIP routines in laser-assisted fabrication schemes targeting micro- and nanofluidic applications.
采用基于硅烷的单层的非线性激光处理，通过表面引发聚合（SIP）在受限区域中制造用于选择性生长聚合物刷的纳米结构化学模板。通过改变激光参数，可以制造出具有从几微米到小于 100nm 范围的横向尺寸的反应性区域。这为研究受限聚合物刷的形态缩放行为提供了一种通用手段。在这里，通过原子转移自由基聚合（ATRP）研究了刺激响应聚合物聚（N-异丙基丙烯酰胺）（PNiPAAm）的表面引发生长。在域边界处的聚合物链延伸到周围的无聚合物区域中。出于这个原因，受限聚合物刷的宽度明显大于其下面的域的宽度。然而，在实验误差范围内，多余的宽度不取决于域的大小。相比之下，当域尺寸小于某个值时，刷的高度下降得越来越多。简单的考虑表明聚合物刷的高度和宽度之间存在几何比例关系。这些结果对于在针对微纳流控应用的激光辅助制造方案中实施 SIP 例程是必不可少的。
