Polymer micro/nano-structured materials have a large variety of applications in carbon capture, gas storage, separation and purification, catalysis, drug delivery, and sensing. Given their diversity of usage, understanding the process routes by which these structures are formed, and achieving fine control over their size, morphology and pore size, as well as the accurate characterisation of their resultant properties is of great interest, both academically and industrially. This work is primarily concerned with generating structure by nonsolvent induced phase separation (NIPS), specifically for a system of poly(2, 6-diphenyl-\textit{p}-phenylene oxide) (PPPO) in good solvent dichloromethane (DCM), and nonsolvent heptane - although the physical processes involved are applicable to a wide range of polymer:solvent:nonsolvent systems. Chapter 1 details the motivation behind this work, providing background information on NIPS, work on the uses and properties of PPPO to date, as well as outlining the underpinning theories behind some of the most frequently used techniques in this thesis: microscopy and scattering. Chapter 2 maps the phase behaviour of this ternary system, exploring the pathways of demixing and the time scales associated with the thermodynamic and kinetic evolution, both of which are vital to determining the final polymer material structure. Chapter 3 uses small angle neutron scattering (SANS) measurements of binary and ternary polymer solutions in order to determine solution structure prior to demixing, and compare. In chapter 4, PPPO materials produced by NIPS are characterised, with specific emphasis on their surface structure and adsorption capabilities. Chapters 5 and 6 both use the acoustic levitation of polymer solution droplets to examine particle formation and directional solidification caused by drying. In chapter 5, polystyrene in DCM is initially used as a model system, and then chapter 6 uses acoustic levitation to examine drying of binary and ternary PPPO solution droplets. Finally, Chapter 7 presents brief closing remarks, and an outlook for future work.