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DNA Driven Assembly at Solid and Liquid Interfaces 10.17863/CAM.13749 Joshi, Darshana 0000000196258433 Eiser, Erika This thesis presents work on the DNA directed assembly of colloids at liquid and solid interfaces under specifically sculpted attractive interactions via depletion forces and/or magnetic fields. The highly specific and thermally reversible nature of binding between two complementary single strands of DNA allows us to encode binding rules among various (solid or liquid) components of the system. The thesis begins by presenting a new approach for introducing mobile DNA linkers on oil droplets, enabling a reversible adsorption of colloids at the oil/water interface. In comparison to previous cumbersome approaches involving expensive biotinylated lipids, this simple method provides a relatively higher grafting density of DNA anchors at the interface. Further, it is possible to kinetically control the surface coverage of oil droplets with colloidal particles while preserving fully ergodic colloidal dynamics on the droplets. The equilibrium nature of the absorbed colloids is illustrated by exploring the quasi-two-dimensional (2d) phase behaviour under the influence of depletion interactions. Colloids bound to the oil water interface are found to be significantly less diffusive compared to their bulk counterparts. Simulation studies from collaboration reaffirm the experimentally observed phase behaviour and the nature of compositional arrest. Further, some preliminary results on the phase behaviour of binary colloidal mixtures at the oil/water interface are also presented. The last section of this thesis demonstrates an approach for creating novel superstructures of DNA coated colloids (DNAcc) directed via an externally applied magnetic field. Raspberry-like and long coaxial skeletons of smaller colloids around larger superparamagnetic colloidal cores in a two component system are shown. The rigidity of these mesoscopic superstructures is enhanced by adding a suitably functionalized third component. Finally, the thesis concludes by presenting various dimensions that have emerged out of this work and are being currently pursued University of Cambridge 2017-10-04 Thesis Doctoral Doctor of Philosophy (PhD) en D.J. thanks the Udayan Care-VCare grant, the Nehru Trust for Cambridge University, the Schlumberger Foundation’s Faculty for the Future Program, and Hughes Hall Santander Bursary Scholarship for the fellowship awards and financial support during her PhD https://www.repository.cam.ac.uk/handle/1810/267825 https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/0f1c19d0-8347-4293-bd10-f8feb3eb1d95/download 87eda9de84448d1f82354d60eee3eb5f https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/492dcad6-7c37-42fa-a69d-5ba49e14f4a6/download f03b7626422af5d6701e871478c6ee6b https://www.rioxx.net/licenses/all-rights-reserved/ Colloids Interfaces self-assembly Smart emulsions DNA functionalization colloidal aggregation