Substrate-dependent structure of grafted polymer films

Hydrogels are water-rich polymer networks made from natural or synthetic polymers, which are widely used in biomaterials, medicine and antifouling. We explore PEG-based hydrogels grafted through a UV-initiated free-radical polymerization, primarily for antifouling applications. Their preparation can be tuned to produce a given polymer mass per surface area, but growth rates vary between substrate types, and is 2-4 times faster on gold than on silicon; two substrate types which are important for biosensors. Previous data point at variations in grafting densities as a reason for this, and to further investigate this, we compare the structures of polymers grafted from surfaces with controlled surface densities of initiators, using dilution of initiators in mixed monolayers of alkylthiols on gold, and organosilanes on silicon.

水凝胶是由天然或合成聚合物构成的富水聚合物网络，广泛应用于生物材料、医学及防污领域。我们研究通过紫外引发自由基聚合接枝的聚乙二醇基水凝胶，其主要应用场景为防污领域。其制备过程可通过调控获得特定的单位表面积聚合物质量，但生长速率因基底类型而异——金基底上的生长速率是硅基底的2-4倍，而这两种基底在生物传感器领域具有重要意义。先前数据表明，接枝密度的差异是导致这一现象的原因。为深入探究此问题，我们通过在金基底的烷基硫醇混合单分子层及硅基底的有机硅烷中稀释引发剂，比较了从具有可控引发剂表面密度的基底接枝所得聚合物的结构。