Sandeep Pal

• The main focus of the thesis is to study the enhancement in the hydrophobicity of an already hydrophobic surface by creating surface structuring on the surface of the crystal. The local structuring and the free energy of interfacial water at the crystal/water interface is analysed by molecular dynamics simulation. An alkane crystal has been taken as the parent model for a hydrophobic surface. Surface structuring were created by either indenting pits on the surface of the crystal or by raising a protrusion on the surface of the crystal. Around all structures the water density was lower and the number of contacts between water and the surface of the crystal decreased due to surface structuring. The difference in the free energy of hydration between planar surface and the structured surface also revealed the increase in the hydrophobicity of the already hydrophobic crystal. Finally a study on the hydrophobicity of a perfluoro-n-alkane crystal is discussed in the final chapter. A qualitative comparison of the water structuring near an alkane and a perfluoro-n-alkane crystal show a higher htdrophobicity in case of a perfluoro-n-alkane crystal than an alkane crystal.