FORMATION OF POLYMER MICROSTRUCTURES BY SELECTIVE DEPOSITION OF POLYION MULTILAYERS USING PATTERNED SELF-ASSEMBLED MONOLAYERS AS A TEMPLATE
FORMATION OF POLYMER MICROSTRUCTURES BY SELECTIVE DEPOSITION OF POLYION MULTILAYERS USING PATTERNED SELF-ASSEMBLED MONOLAYERS AS A TEMPLATE
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DOI:
10.1021/ma00126a040
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发表时间:
1995-10-23
期刊:
影响因子:
5.5
通讯作者:
WHITESIDES, GM
中科院分区:
文献类型:
--
作者:
HAMMOND, PT;WHITESIDES, GM
I. Introduction. Techniques for fabrication of ionic multilayers by self-assembly have been of great interest in the polymer science andorganic thin films com-munities. 1-4 These techniques take advantage of the ionic interactions of oppositely charged molecules or macromolecules to build thin films sequentially, one monolayer at a time; 1 the ability to control the archi-tecture of these films and the relative versatility of the method (compared to LB film techniques) have contributed to the rapid incorporation of the method into materials research. Systems that have been prepared by this procedure include conducting polymers and electroluminescent films, 5 and those that integrate layers of ceramic and metallic compounds. 6-8 We have previously described methods to pattern micron-sized features of a large variety of functionalized alkanethiolate self-assembled monolayers (SAMs) on gold using microcontact printing («CP). 910 This method utilizes a poly (dimethylsiloxane) stamp molded from a photolithographic master to transfer an image using an alkanethiol “ink”, with feature sizes down to 100 nm. In the following communication, we have explored the use of patterned SAMs as a template for the selective deposition of ionically charged polymer multilayers. For this initial study, we used common polyelectrolytes: sulfonated polystyrene (SPS), poly (diallyldimethylam-monium chloride)(PDAC), and poly (allylamine hydrochloride)(PAH).II. Experimental Section. Gold substrates were prepared by electron beam evaporation of 50 A of titanium as an adhesion-promoting layer, followed by 200 A of gold, onto silicon wafers (Si/Si02)(Silicon Sense). UsingpCP, the gold surface was patterned with 2.5/imlines of hexadecanethiol CH3 (CH2) isSH (CH3) or 16-mercaptohexadecanoic acid HS (CH2) igCOOH (COOH), separated by 3.5 pm spaces. For most cases, gold substrates were then dipped into a 5 mM solution of oligo-(ethylene glycol)-terminated alkanethiol SH (CH2) u-(OCH2CH2LOH (EGn, n= 2—7) for 10 s to cover the remaining gold regions andthen rinsed with ethanol and heptane. The oligo (ethylene glycol)-terminated alkanethiol was used to prevent adsorption of the ionic polymers onto the regions of bare gold in the pattern;