Copper based superhydrophobic surfaces are fabricated using a laser electrodeposited composite method, which is able to form a dual rough microstructure. It is found that the static contact angles on these special microstructure surfaces are bigger than 150° and rolling angles are smaller than 5° when there is no low energy material coating on surfaces. It is also found that the pressure drops on microchannel surfaces composed with these microstructures show an increasing trend with the widening of channel. Under the condition of laminar flow, they are obviously smaller on superhydrophobic microchannels than on a smooth channel. Owing to the superhydrophobic structures, the friction factor reduces compared with a smooth surface. The biggest reduction value is 48·8, and the smallest is 46·9.
VaranasiKK, DengT, ChamarthyP, ChauhanS, de BockP, KulkarniA, MandrusiakG, RushB, RussB, DenaultL, WeaverS, GernerF, LelandQ and YerkesK: ‘Engineered nanostructures for high thermal conductivity substrates’, Proc. Nanotech Conf. and Expo 2009, Houston, TX, USA, May 2009, Nano Science and Technology Institute.
2.
WangY and MehernoshG: ‘Measurement of thermal conductivity and heat pipe effect in hydrophilic and hydrophobic carbon papers’, Int. J. Heat Mass Transfer, 2013, 60, 134–142.
3.
HaoT, MaX, LanZ, LiN and ZhaoY: ‘Effects of superhydrophobic and superhydrophilic surfaces on heat transfer and oscillating motion of an oscillating heat pipe’, J. Heat Transfer, 2014, 136, (8), 082001.
4.
ChoiC.-H, WestinK, JohanA and BreuerKS: ‘Apparent slip flows in hydrophilic and hydrophobic microchannels’, Phys. Fluids, 2003, 15, (10), 2897–2902.
5.
MuradS, LuoL and ChuL.-Y: ‘Anomalous flow behavior in nanochannels: a molecular dynamics study’, Chem. Phys. Lett., 2010, 492, (4–6), 285–289.
6.
GogteS, VorobieffP, TruesdellR, MammoliA, van SwolF, ShahP and Jeffrey BrinkerC: ‘Effective slip on textured superhydrophobic surfaces’, Phys. Fluids, 2005, 17, (5), 051701.
7.
QianB.-T and ShenZ.-Q: ‘Super-hydrophobic CuO nanoflowers by controlled surface oxidation on copper’, J. Inorg. Mater., 2006, 3, 038.
LaD.-D, NguyenTA, LeeS, KimJW and KimYS: ‘A stable superhydrophobic and superoleophilic Cu mesh based on copper hydroxide nanoneedle arrays’, Appl. Surf. Sci., 2011, 257, (13), 5705–5710.
10.
WangS, FengL and JiangL: ‘One-step solution-immersion process for the fabrication of stable bionic superhydrophobic surfaces’, Adv. Mater., 2006, 18, (6), 767–770.
11.
TianCF, ZhangFL, CaiHH, FangJX and DingBJ: ‘“Flower-like” micropillars of copper with porous nanowalls as effective hydrophobic surface’, Mater. Sci. Technol., 2013, 29, (4), 446–450.
12.
ZhaoH, LawK.-Y and SambhyV: ‘Fabrication, surface properties, and origin of superoleophobicity for a model textured surface’, Langmuir, 2011, 27, (10), 5927–5935.
13.
OuJ, PerotB and RothsteinJP: ‘Laminar drag reduction in microchannels using ultrahydrophobic surfaces’, Physics Fluids, 2004, 16, (12), 4635.
14.
ChoiC.-H, UlmanellaU, KimJ, HoC-M and KimC.-J: ‘Effective slip and friction reduction in nanograted superhydrophobic microchannels’, Phys. Fluids, 2006, 18, (8), 087105–087108.
15.
WatanabeK, UdagawaY and UdagawaH: ‘Drag reduction of newtonian fluid in a circular pipe with a highly water-repellent wall’, J. Fluid Mech., 1999, 381, 225–238.
ChenW, FadeevAY, HsiehMC, ÖnerD, YoungbloodJ and McCarthyTJ: ‘Ultrahydrophobic and ultralyophobic surfaces: some comments and examples’, Langmuir, 1999, 15, (10), 3395–3399.
20.
PatankarNA: ‘On the modeling of hydrophobic contact angles on rough surfaces’, Langmuir, 2003, 19, (4), 1249–1253.
21.
CassieABD and BaxterS: ‘Wettability of porous surfaces’, Trans. Faraday Soc., 1944, 40, 546–551.
22.
OlssonA, StemmeG and StemmeE: ‘Diffuser-element design investigation for valve-less pumps’, Sens. Actuators A, 1996, 57A, (2), 137–143.
23.
FukudaK, TokunagaJ, NobunagaT, NakataniT, IwasakiT and KunitakeY: ‘Frictional drag reduction with air lubricant over a super-water-repellent surface’, J. Mar. Sci. Technol., 2000, 5, (3), 123–130.
24.
BlevinsRD: ‘Applied fluid dynamics handbook’, Vol. 1, 568; 1984 New York, Van Nostrand Reinhold Co.
