Photonic crystals in biology - NanoTR-VI

PPoster Session, Thursday, June 17Theme F686 - N1123Microwave-Assisted Deposition of Microwire Patterns of Metal Nanoparticles1UUursoy OlgunUP P*1PDepartment of Chemistry, Sakarya University, Sakarya 54187, TurkeyAbstract-Nanoparticles were self-assembled as organized microwire patterns on various substrates due to the stick-slip motion of the contactline during the microwave evaporation of solvent. The colloid solutions of 0.03% (w/v) nanoaluminum in 10% (v/v) poly(dimethylsiloxane)-acetone were used to self-assemble the microwire patterns of Al on glass substrates, which were dipped into the solution and held against thewall. Also, the colloids of 0.001% (w/v) nanosilver prepared in acetone solution of 33.3% (v/v) chloroform, 16.6% (v/v)poly(dimethylsiloxane) and 0.3% (v/v) Tween-20 were utilized for the deposition of the microwire patterns under the microwave heating at51-55 °C. The rapid self-assembly process was demonstrated under the microwave and the width of microwires was about 1-20 m dependingon the concentration of the nanoparticles. Processing of particles to produce surface patterns and their thin films will be presented.The microwave-assisted self-organization of colloidalparticles in confining aqueous droplets was reported for thepreparation of photonic band gap materials [1]. Themicrowave-assisted synthesis and the in-situ self-assembly ofcoaxial Ag/C nanocables have been studied [2]. Although themicrowave synthesis of metal nanoparticles has been studiedin the literature, the microwave processing of the colloids ofmetal nanoparticles has not been investigated in detail. Theevaporation induced self-assembly of zeolite patterns wasreported at room temperature recently [3].Here, the deposition of aluminum and silver microwires wasdirected by the evaporation-induced self-assembly ofnanoparticles under the microwave heating [4]. Compared tothe conventional heating, the microwave radiation had manyadvantages, such as very short time heating, homogeneousenergy transfer to the liquid and reduced bubble formation insolution. The formation of microwire patterns was due to thestick-slip dynamics of the contact line on the surface of thesubstrates. By using the microwave energy, the rapid selfassemblyof the microwires from the metal nanoparticles wasachieved within a few minutes for the first time.The contact line deposition of nanoparticles has been studiedby several groups to prepare micropatterns of variousmaterials. In this study, the effects of using microwave heatingwere explored for the first time to accelerate the particledeposition process. As shown in Figure 1, the role ofmicrowave during the stick-slip motion of contact line wasFigure 2: The images of nanoaluminum and nanosilvermicrowire patterns deposited on glass substrates at 55 C undermicrowave heating [4].20 °C without heating, at 40 °C with conventional heating andat 55 °C with microwave heating. As demonstrated in Figure2, the microwire patterns produced using the microwaveheating are very different for nano Al and Ag particles [4].In summary, it was demonstrated that the colloidal selfassemblyof particles under microwave is an efficient methodto produce micropatterns of nanoparticles. The microwiredeposition process presented in this study is relatively simplecompare to the previous patterning techniques. The use ofphotoresist layer, micropatterned mask, monolayer coatingand molded patterns is not required. As a result of thesefindings, it was concluded that the colloids of aluminum andsilver nanoparticles are suitable for the rapid self-assembly ofthe microwire patterns under the microwave heating.*Corresponding author: HTuolgun@sakarya.edu.trTFigure 1. The mechanism of microwire deposition demonstrated bythe stick-slip dynamics of the contact line [4].investigated using the colloids of nano Al and Ag particles.The colloid solutions of 0.03%(w/v) nanoaluminumcontaining 10%(v/v) PDMS were placed in glass vials and thedeposition of microwires on the wall surface was carried out at[1] S.H. Kim, S.Y. Lee, G.R. Yi, D.J. Pine, S.M. Yang, J. Am. Chem.Soc. 128, 10897, (2006).[2] J.C. Yu, X.L. Hu, L.B. Quan, L.Z. Zhang, Chem. Commun. 21,2704, (2005).[3] U. Olgun, V. Sevinç, Powder Tech. 183, 207, (2008).[4] U.Olgun. ACS Appl. Mater. Interfaces. 2(1), 28, (2010).6th Nanoscience and Nanotechnology Conference, zmir, 2010 653