Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, USA.
Langmuir. 2009 Dec 1;25(23):13448-55. doi: 10.1021/la901785t.
This Article describes a facile method to prepare smooth and homogeneous polymer brush surfaces of variable grafting density from a solid surface by combining Langmuir-Blodgett (LB) deposition with surface-initiated atom transfer radical polymerization (SI-ATRP). This method is successfully demonstrated by the preparation of thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) brush surfaces on smooth silicon and quartz substrates. With the custom-synthesized inert diluent whose chemical structure, except end-functionality, is the same as that of the reactive initiator, smooth and chemically homogeneous mixed monolayers of initiators and inert diluents are immobilized on a solid surface by LB deposition, allowing the further variation of the grafting density of PNIPAM brushes grafted from the initiator monolayers of varied initiator coverage. With the optimized molar ratio of deactivator, Cu(II) in the Cu(I)-ligand catalyst complex, the brush thickness of PNIPAM brushes at varied grafting density is controlled to grow nearly linearly with reaction time while smoothness and chemical homogeneity of PNIPAM brushes are achieved. For the demonstrated PNIPAM brush surfaces, the thermoresponsive characteristics of PNIPAM brushes are also verified. This combined LB-ATRP method can be applied to graft a variety of polymer brushes, including polyelectrolytes and block copolymers, from different solid substrates.
本文描述了一种简便的方法，可通过将 Langmuir-Blodgett（LB）沉积与表面引发原子转移自由基聚合（SI-ATRP）相结合，从固体表面制备具有不同接枝密度的光滑均一聚合物刷表面。该方法通过在光滑的硅和石英基底上制备温敏性聚（N-异丙基丙烯酰胺）（PNIPAM）刷表面得到了成功验证。使用我们合成的惰性稀释剂，其化学结构除端基功能外与反应性引发剂相同，通过 LB 沉积将引发剂和惰性稀释剂的光滑且化学均匀的混合单层固定在固体表面上，从而可以进一步改变从具有不同引发剂覆盖率的引发剂单层接枝的 PNIPAM 刷的接枝密度。通过优化的失活剂摩尔比，Cu（I）-配体催化剂络合物中的 Cu（II），在不同接枝密度下 PNIPAM 刷的刷厚度可以控制为随反应时间几乎呈线性增长，同时实现了 PNIPAM 刷的光滑度和化学均匀性。对于所展示的 PNIPAM 刷表面，还验证了 PNIPAM 刷的温敏特性。这种组合的 LB-ATRP 方法可用于从不同的固体基底上接枝各种聚合物刷，包括聚电解质和嵌段共聚物。
