Electrokinetic Study on Tunable 3D Nanochannel. Networks Constructed by Spatially Controlled. Nanoparticle Assembly

Transcription

1 Electronic Supplementary Material (ESI) for Lab on a Chip. Thi journal i The Royal Society of Chemitry 014 Electrokinetic Study on Tunable 3D Nanochannel Network Contructed by Spatially Controlled Nanoparticle Aembly Eunpyo Choi, 1 Kilung Kwon, 1 Daejoong Kim, 1, and Jungyul Park 1, 1 Department of Mechanical Engineering, Sogang Univerity, 35 Baekbeom-ro, Mapo-gu, Seoul, 11-74, Korea 1

2 S.I Fabrication proce for PDMS microfluidic channel with multilayered deign Fig. S1 Scheme of the fabrication proce for PDMS microfluidic channel with multilayered deign. Fig. S1(a) - (d) how chematic diagram that decribe the procedure for fabricating microfluidic device with multilayered deign. We fabricated microfluidic chip uing the tandard oft lithography: 1 (a) A 4-inch ilicon wafer wa pin-coated with negative photoreit (SU-8 005, MicroChem Inc., target: 5 μm to 100 μm), and then the coated ilicon wafer wa oft-baked for everal minute. The wafer wa expoed under a mak uing an aligner and placed on a hot-plate for everal minute of pot-expoure baking, followed by a hort relaxation time. Pot-expoure baking wa followed by development at room temperature, after which the whole wafer wa rined with iopropyl alcohol (IPA) to clean the reidue from the wafer. Subequently, SU wa patterned on the firt SU-8 layer (target: 100 μm, thi layer i for the deep channel) with ame proce a above. (b) A Polydimethyliloxane (PDMS) precuror (Sylgard 184 Silicone Elatomer, Dow Corning) and a curing agent were mixed at a ratio of 10 to 1, baed on weight. Before the PDMS mixture wa poured onto the fabricated mater, the mater wa ilanized with (tridecafluoro-1,1,,,-tetrahydrooctyl)-1-trichloroilane (Sigma Chemical Co., St. Loui, MO, USA) to allow eaier removal of the PDMS after curing. The PDMS mixture wa poured onto the mater and cured at 95 C for 1 h. (c) Then, the cured PDMS channel wa

3 peeled off from the mater, cut and punched to connect microtube. (d) The PDMS device were directly bonded to a gla ubtrate without any urface treatment and then they were treated with oxygen plama under 50 ccm of O and 70 W for 40 (Cute-MP, Femto Science, Korea). 3

4 S.II Reproducibility Fig. S I-V plot for decribing (a) the run to run, (b) device to device, (c) total, and (d) overall immerged data with tandard error bar. Fig S (a), (b), (c), and (d) how the I-V plot for decribing the run to run, the device to device, the total and the overall immerged data with tandard error bar, repectively. The fixed condition i a follow; P-NP: 300 nm, height of hallow channel: 5 μm, width of hallow channel: 00 μm. Each experiment wa conducted 5 time and hown with tandard error. The maximum tandard error i ± na for the run to run experiment and it value i much lower than the device to device cae (± na). Baed on thee run to run and device to device reproducibility experiment, we re-plotted the total tandard error bar a hown in Fig. S(c). In thi paper, all the I-V curve are plotted by uing thi total tandard error. 4

5 S.III Evolution of the pattern of the ion depletion layer Fig. S3 Time equence image of the depletion layer pattern evolution. Fig. S3 how the time equence image of the depletion layer pattern evolution. In thi cae, we ued the h with 5 um, w with 400 um, 300 nm of diameter of ilica nanoparticle, 0.1 mm of KCl olution at value of ph 5.6 with FITC fluorecent dye, and +30 V of applied voltage. When the ICP were generated, mall ize of periodic undulation pattern of depletion layer were formed. Subequently, thee mall layer became merged into one larger depletion layer and extended over time but there till exited ejecting vortice which diturb the tability of depletion layer at each ide wall by the corner effect. 4 5

6 S.IV Effective cro ectional area of ideally cloe-packed homogeneou nanoparticle into the FCC tructure Fig. S4 Effective cro ectional area of ideally cloe-packed homogeneou nanoparticle into the FCC tructure Fig. S4 how a unit of the effective cro ection area ( A u ) of the ideally cloe-packed homogeneou nanoparticle on the {100} plane of the FCC tructure. follow: A u can be decribed a A u a D ( n ) (S1) here, the former term, a, i the unit of the cro ectional area of the {100} plane and the latter term i the unit of the cro ectional area of the cloed packed particle within the {100} plane. A ubtituting the a D n for Eq. (S1), the become following expreion: A u 6

7 A u D n ( Dn ) ( ) 0.43Dn 0.15a (S) Since the cloe-packed nanoparticle with FCC tructure ha the ame packing efficiency, the ratio i inenitive to the width (w ) and the height (h ) of the hallow channel. In thi reaon, the effective cro ectional area of the hallow channel, A, can be etimated a A 0. 15w h, i.e % of the A. REFERENCES 1. E. Choi, H. K. Chang, C. Y. Lim, T. Kim and J. Park, Lab chip, 01, 1,