We measured water-CO2 contact angles on a smooth quartz surface (RMS surface roughness similar to 40 nm) as a function of pressure and temperature. The advancing water contact angle theta was 0 degrees at 0.1 MPa CO2 pressure and all temperatures tested (296-343 K); theta increased significantly with increasing pressure and temperature (theta = 35 degrees at 296 K and theta = 56 degrees at 343 K at 20 MPa). A larger theta implies less structural and residual trapping and thus lower CO2 storage capacities at higher pressures and temperatures. Furthermore we did not identify any significant influence of CO2-water equilibration on theta. Moreover, we measured the CO2-water interfacial tension gamma and found that gamma strongly decreased with increasing pressure up to similar to 10 MPa, and then decreased with a smaller slope with further increasing pressure gamma also increased with increasing temperature. (C) 2014 Elsevier Inc. All rights reserved.