The phase behaviour and the structure formation of solutions of poly(2,6-dimethyl-1,4-phenylene ether) (PPE) in cyclohexanol and decalin have been studied. Interesting structures were formed and the morphologies depended on the rate at which the solutions were cooled. This was caused by the competition between melting—crystallization, vitrification and phase separation. Differential scanning electron microscopy (SEM) was used to study the different morphologies. Porous materials can be used as membranes. Hollow porous PPE fibres were spun.