This dissertation focuses on the synthesis, characterization, and application of amphiphilic bottlebrush copolymers and bottlebrush electrolytes, emphasizing how variations in polymer shape and size significantly influence interfacial assembly kinetics, packing efficiency, and mechanical properties. The use of a highly reactive yet stable ruthenium benzylidene catalyst (Grubbs catalyst) enabled the facile synthesis of bottlebrush polymers with different backbone and side-chain degrees of polymerization through ring-opening metathesis polymerization. This versatility allowed precise control over the resulting polymers’ shape and size. Notably, this work explores the assembly behavior of amphiphilic bottlebrush random and block copolymers at liquid interfaces, revealing distinct interfacial assembly kinetics, packing efficiency, and mechanical properties depending on the microstructure. Additionally, bottlebrush polyelectrolytes containing acrylic acid repeating units were synthesized and studied for their co-assembly with oligomeric, amine-containing counterparts in the oil phase, highlighting design principles for using bottlebrush polyelectrolytes as soft nanoparticles in liquid printing techniques. Furthermore, the amphiphilicity of core-shell bottlebrush copolymers, comprising a pH-responsive core with a hydrophobic shell, was shown to be adjustable by modulating the water pH, triggering an inversion process governed by the enthalpic penalty associated with inter-side-chain steric repulsions. Lastly, the shape and size of bottlebrush polymers was tuned during synthesis by adjusting the monomer/catalyst ratio, and through embedding redox-responsive disulfide groups along the backbone. Disulfide cleavage triggered backbone degradation, altering the final shape and size of the bottlebrush polymers.