Abstract
The surface modification is indispensable to facilitate new functional applications of micro/nanofluidics devices. Among many modification techniques developed so far, the photo-induced chemical modification is the most versatile method in terms of robustness, process simplicity, and feasibility of chemical functionality. In particular, the method is useful for closed spaces, such as post-bonded devices. However, the limitation by optical diffraction limit is still a challenging issue in scaling down the pattern sizes to nanoscale. Here, we demonstrated a novel surface modification on sub-100 nm scale utilizing the novel optical near-field (ONF) generated on nanostructures of photocatalyst (TiO2). The minimum pattern size of 40 nm, which was much smaller than diffraction limit, was achieved using a visible light source (488 nm) and a conventional irradiation setup. The controllability of pattern size by light intensity, the feasibility of functionality, and the non-contact working mode have impacts on surface patterning of post-bonded micro/nanofluidics devices. It is also worthy to note that our results verified for the first time the ONF on nanostructures of non-metal materials and its ability to manipulate the chemical reaction on nanoscale.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Bunimovich Y, Ge G, Ries R, Beverly K, Hood L, Heath J (2004) Electrochemically programmed, spatially selective biofunctionalization of silicon wires. Langmuir 20:10630–10638
Delamarche E, Juncker D, Schmid H (2005) Microfluidics for processing surfaces and miniaturizing biological assays. Adv Mater 17:2911–2933
Ganesan R, Kratza K, Lendlein A (2010) Multicomponent protein patterning of material surfaces. J Mater Chem 20:7322–7331
Hibara A, Nonaka M, Hisamoto H, Uchiyama K, Kikutani Y, Tokeshi M, Kitamori T (2002) Stabilization of liquid interface and control of two-phase confluence and separation in glass microchips by utilizing octadecylsilane modification of microchannels. Anal Chem 74:1724–1728
Hibara A, Takumi S, Kim H-B, Tokeshi M, Ooi T, Nakao M, Kitamori T (2003) Liquid properties investigation by time-resolved fluorescence measurements. Anal Chem 36:605–612
Huo F, Zheng Z, Zheng G, Giam LR, Zhang H, Mirkin CA (2008) Polymer pen lithography. Science 321:1658–1660
Jane A, Dronov R, Hodges A, Voelcker NH (2009) Porous silicon biosensors on the advance. Trends Biotechnol 27:230–240
Juodkazis S, Yamaguchi A, Ishii H, Matsuo S, Takagi H, Misawa H (2001) Photo-electrochemical deposition of platinum on TiO2 with resolution of twenty nanometers using a mask elaborated with electron-beam lithography. Jpn J Appl Phys 40:4246–4251
Kawazoe T, Ohtsu M, Inao Y, Kuroda R (2007) Exposure dependence of the developed depth in nonadiabatic photolithography using visible optical near fields. J Nanophoton 1:011595
Kawazoe T, Fujiwara H, Kobayashi K, Ohtsu M (2009) Visible light emission from dye molecular grains via infrared excitation based on the nonadiabatic transition induced by the optical near field. J Sel Top Quantum Electron 15:1380–1386
König T, Sekhara YN, Santer S (2012) Surface plasmon nanolithography: impact of dynamically varying near-field boundary conditions at the air–polymer interface. J Mater Chem 22:5945–5950
Le THH, Mawatari K, Pihosh Y, Kawazoe T, Yatsui T, Ohtsu M, Tosa M, Kitamori T (2011) Optical near-field induced visible response photoelectrochemical water splitting on nanorod TiO2 Appl. Phys Lett 99:213105–213108
Le THH, Mawatari K, Hasumoto N, Pihosh Y, Kitamura K, Kawazoe T, Yatsui T, Naruse M, Ohtsu M, Kitamori T (2012) Optical near-field induced chemical partial hydrophobic/hydrophilic modification with sub-diffraction limit resolution. In: Proceedings of the 16th μTAS conference, pp 222–224
Luo X, Ishihara T (2004) Subwavelength photolithography based on surface-plasmon polariton resonance. Opt Express 12:3055
Mawatari K, Kubota S, Xu Y, Priest C, Sedev R, Ralston J, Kitamori T (2013) Femtoliter droplet handling in nanofluidic channels: a Laplace nanovalve. Anal Chem 84:10812–10816
Menard E (2007) Micro- and nanopatterning techniques for organic electronic and optoelectronic systems. Chem Rev 107:1117–1160
Mendes PM, Yeung CL, Preece JA (2007) Bio-nanopatterning of surfaces. Nanoscale Res Lett 2:373–384
Park I, Li Z, Pisano AP, Williams RS (2007) Selective surface functionalization of silicon nanowires via nanoscale Joule heating. Nano Lett 7:3106–3111
Priest C (2010) Surface patterning of bonded microfluidic channels. Biomicrofluidic 4(3):32206–32219
Pu Q, Yun JS, Temkin H, Liu SR (2004) Ion-enrichment and ion-depletion effect of nanochannel structures. Nano Lett 4:1099–1103
Qi M, Lidorikis E, Rakich PK, Johnson SG, Joannopoulos JD, Ippen EP, Smith HI (2004) A three-dimensional optical photonic crystal with designed point defects. Nature 429:538–542
Tseng AA, Notargiacomo A, Chen TP (2005) Nanofabrication by scanning probe microscope lithography: a review. J Vac Sci Technol B 23:877–894
Tsukahara T, Hibara A, Ikeda K, Kitamori T (2007) NMR study of water molecules confined in extended nanospaces. Angew Chem Int Ed 46:1180–1183
Ueno K, Juodkazis S, Shibuya T, Yokota Y, Mizeikis V, Sasaki K, Misawa H (2008) Nanoparticle plasmon-assisted two-photon polymerization induced by incoherent excitation source. J Am Chem Soc 130:6928–6929
Valev VK, De Clercq B, Biris CG, Zheng X, Vandendriessche S, Hojeij M, Denkova D, Jeyaram Y, Panoiu NC, Ekinci Y, Silhanek AV, Volskiy V, Vandenbosch GAE, Ameloot M, Moshchalkov VV, Verbiest T (2012) Distributing the optical near-field for efficient field-enhancements in nanostructures. Adv Opt Mater 24:208–215
West J, Becher M, Tombrink S, Manz A (2008) Micro total analysis systems: latest achievements. Anal Chem 80:4403–4419
Wouters D, Schubert US (2004) Nanolithography and nanochemistry: probe-related patterning techniques and chemical modification for nanometer-sized devices. Angew Chem Int Ed 43:2480–2495
Xia Y, Whitesides GM (1998) Soft lithography. Angew Chem Int Ed 37:550–575
Yatsui T, Hirata K, Nomura W, Tabata Y, Ohtsu M (2008) Realization of an ultra-flat silica surface with angstrom-scale average roughness using nonadiabatic optical near-field etching. Appl Phys B 93:55–57
Yonemitsu H, Kawazoe T, Kobayashi K, Ohtsu M (2005) Nonadiabatic photochemical reaction and application to photolithography. J Lumin 122:230–233
Yukutake S, Kawazoe T, Yatsui T, Hirata K, Nomura W, Kitamura K, Ohtsu M (2010) Selective photocurrent generation in the transparent wavelength range of a semiconductor photovoltaic device using a phonon-assisted optical near-field process. Appl Phys B 99:415–422
Acknowledgments
This work was partially supported by JSPS Core-to-Core Program and the Grant-in-Aid for Specially Promoted Research. We also would like to thank to the Research Hub for Nano Characterization Center at the University of Tokyo for SEM measurement.
Author information
Authors and Affiliations
Corresponding author
Electronic supplementary material
Below is the link to the electronic supplementary material.
Rights and permissions
About this article
Cite this article
Le, T.H.H., Mawatari, K., Pihosh, Y. et al. Novel sub-100 nm surface chemical modification by optical near-field induced photocatalytic reaction. Microfluid Nanofluid 17, 751–758 (2014). https://doi.org/10.1007/s10404-014-1361-7
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10404-014-1361-7