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Controllable assembly of silver nanoparticles induced by femtosecond laser direct writing

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ABSTRACT

We report controllable assembly of silver nanoparticles (Ag NPs) for patterning of silver microstructures. The assembly is induced by femtosecond laser direct writing (FsLDW). A tightly focused femtosecond laser beam is capable of trapping and driving Ag NPs to form desired micropatterns with a high resolution of ∼190 nm. Taking advantage of the ‘direct writing’ feature, three microelectrodes have been integrated with a microfluidic chip; two silver-based microdevices including a microheater and a catalytic reactor have been fabricated inside a microfluidic channel for chip functionalization. The FsLDW-induced programmable assembly of Ag NPs may open up a new way to the designable patterning of silver microstructures toward flexible fabrication and integration of functional devices.

No MeSH data available.


Silver microheater and catalytic microreactor fabricated by FsLDW-induced controllable assembly of Ag NPs. (a)–(c) Heating process of a microheater integrated within a microfluidic channel. A microbubble could be clearly observed, indicating the heating of the solvent. (d)–(f) Catalytic decomposition of H2O2 inside a silver microreactor. (e) Gas bubbles appeared as soon as H2O2 was injected into the channel; (f) 2 s later, the bubble grew bigger. The scale bar is 20 μm.
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Figure 6: Silver microheater and catalytic microreactor fabricated by FsLDW-induced controllable assembly of Ag NPs. (a)–(c) Heating process of a microheater integrated within a microfluidic channel. A microbubble could be clearly observed, indicating the heating of the solvent. (d)–(f) Catalytic decomposition of H2O2 inside a silver microreactor. (e) Gas bubbles appeared as soon as H2O2 was injected into the channel; (f) 2 s later, the bubble grew bigger. The scale bar is 20 μm.

Mentions: For practical applications, a silver microheater was fabricated by FsLDW-induced controllable assembly of Ag NPs (figure 6). Five parallel microwires were fabricated between two gold electrodes. The patterned silver structure is conductive (see supporting information figure S1), when a voltage of 2 V was supplied on the microheater, a bubble rose from the water within 1.5 s, indicating the high heating efficiency. With continuous heating, the gas bubble grew larger, indicating the increase of local temperature. Compared with general microheaters fabricated by conventional craft, FsLDW fabrication was compatible with many substrates ranging from inorganic glass and silicon to organic polymers such as polydimethylsiloxane (PDMS) and polymethyl methacrylate (PMMA). In this regard, the technique would be potentially important to multifunction integration of microfluidic chips. FsLDW-induced controllable assembly of Ag NPs enables flexible patterning of silver at any desired place. In addition to the microheater, silver microstrucutures could also be integrated with microfluidic devices for catalysis and pump applications. As shown in figures 6(d)–(f), we explored Ag-catalyzed decomposition of H2O2 inside a microfluidic channel; the generation of O2 could be observed as soon as H2O2 was injected into the microchannel. Since the Ag catalysts could be flexibly placed at any desired position, the generated oxygen bubble could be potentially used as a pump for directional transport of target objects or to guide the flow inside a microfluidic device [64].


Controllable assembly of silver nanoparticles induced by femtosecond laser direct writing
Silver microheater and catalytic microreactor fabricated by FsLDW-induced controllable assembly of Ag NPs. (a)–(c) Heating process of a microheater integrated within a microfluidic channel. A microbubble could be clearly observed, indicating the heating of the solvent. (d)–(f) Catalytic decomposition of H2O2 inside a silver microreactor. (e) Gas bubbles appeared as soon as H2O2 was injected into the channel; (f) 2 s later, the bubble grew bigger. The scale bar is 20 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
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Figure 6: Silver microheater and catalytic microreactor fabricated by FsLDW-induced controllable assembly of Ag NPs. (a)–(c) Heating process of a microheater integrated within a microfluidic channel. A microbubble could be clearly observed, indicating the heating of the solvent. (d)–(f) Catalytic decomposition of H2O2 inside a silver microreactor. (e) Gas bubbles appeared as soon as H2O2 was injected into the channel; (f) 2 s later, the bubble grew bigger. The scale bar is 20 μm.
Mentions: For practical applications, a silver microheater was fabricated by FsLDW-induced controllable assembly of Ag NPs (figure 6). Five parallel microwires were fabricated between two gold electrodes. The patterned silver structure is conductive (see supporting information figure S1), when a voltage of 2 V was supplied on the microheater, a bubble rose from the water within 1.5 s, indicating the high heating efficiency. With continuous heating, the gas bubble grew larger, indicating the increase of local temperature. Compared with general microheaters fabricated by conventional craft, FsLDW fabrication was compatible with many substrates ranging from inorganic glass and silicon to organic polymers such as polydimethylsiloxane (PDMS) and polymethyl methacrylate (PMMA). In this regard, the technique would be potentially important to multifunction integration of microfluidic chips. FsLDW-induced controllable assembly of Ag NPs enables flexible patterning of silver at any desired place. In addition to the microheater, silver microstrucutures could also be integrated with microfluidic devices for catalysis and pump applications. As shown in figures 6(d)–(f), we explored Ag-catalyzed decomposition of H2O2 inside a microfluidic channel; the generation of O2 could be observed as soon as H2O2 was injected into the microchannel. Since the Ag catalysts could be flexibly placed at any desired position, the generated oxygen bubble could be potentially used as a pump for directional transport of target objects or to guide the flow inside a microfluidic device [64].

View Article: PubMed Central - PubMed

ABSTRACT

We report controllable assembly of silver nanoparticles (Ag NPs) for patterning of silver microstructures. The assembly is induced by femtosecond laser direct writing (FsLDW). A tightly focused femtosecond laser beam is capable of trapping and driving Ag NPs to form desired micropatterns with a high resolution of ∼190 nm. Taking advantage of the ‘direct writing’ feature, three microelectrodes have been integrated with a microfluidic chip; two silver-based microdevices including a microheater and a catalytic reactor have been fabricated inside a microfluidic channel for chip functionalization. The FsLDW-induced programmable assembly of Ag NPs may open up a new way to the designable patterning of silver microstructures toward flexible fabrication and integration of functional devices.

No MeSH data available.