Microscale temperature gradient in liquid is a driving factor behind many microscopic physical phenomena in liquid. Molecules and particles in liquid can migrate along temperature gradient and at micrometric spatial scale this effect is known as microscale thermophoresis. Overshadowed in macroscopic environment by thermal convection, this effect becomes faster and dominant in microscale. Microscale thermophoresis is the basis of applications in bioanalytics, study of protein stability thanks to its commercialization. In addition, fundamental research in thermophoresis has also progressed a lot in last decade in the context of thermoplasmonics. Plasmonic nanoparticles under laser irridation at resonance wavelength become nanosources of heat. This thesis work utilized this phenomenon to create microscale temperature gradient in microscale liquid systems to investigate thermophoresis of particles and molecules. Temperature gradient is created by illuminating a homogenous carpet of gold nanoparticle at their resonance wavelength.

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