Selective Self-Organization of Colloids on Patterned Polyelectrolyte Templates
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- 作者：Kevin M. Chen ; Xueping Jiang ; Lionel C. Kimerling ; and Paula T. Hammond
- 刊名：Langmuir
- 出版年：2000
- 出版时间：October 3, 2000
- 年：2000
- 卷：16
- 期：20
- 页码：7825 - 7834
- 全文大小：719K
- 年卷期：v.16,no.20(October 3, 2000)
- ISSN：1520-5827
文摘
Submicron-sized colloidal particles have been self-organized into patterned arrangements on a substrateusing a novel technique. At the substrate, a polyelectrolyte multilayer film has been deposited onto achemically patterned surface; subsequently, the polyelectrolyte surface is immersed in an aqueous colloidalsuspension of bare SiO2 microspheres or functionalized polystyrene latex particles. The colloids self-organize at the surface, driven by the spatially varied electrostatic and secondary interactions betweenthe colloid and the substrate. The polyelectrolyte platform provides a strong bond to the colloids, impartingmechanical robustness which enables postprocessing of the patterned assemblies. An important advantageto this approach is that the use of a polyelectrolyte multilayer platform opens up the possibility of introducingfunctionality into the underlying layers. We have demonstrated control over the density and selectivityof particle adsorption. Three mechanisms have been used to control adsorption: (i) pH of the colloidsuspension, which determines the ionization of the uppermost surface of the polyelectrolyte multilayer;(ii) ionic strength of the suspension, which determines the extent of charge screening about the colloid andpolyelectrolyte; and (iii) concentration of added surfactant, which causes charge screening and introduceshydrophobic interactions between the surfactant and polyelectrolyte. Finally, an energy adsorption modelis presented.