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A series of six low molecular weight elastomers with hydrogen bonding end-groups have been designed, synthesised and studied. The poly(urethane) based elastomers all contained essentially the same hard block content (ca. 11%) and differ only in the nature of their end-groups. Solution state 1 H NMR spectroscopic analysis of model compounds featuring the end-groups demonstrate that they all exhibit very low binding constants, in the range 1.4 to 45.0 M-1 in CDCl 3 , yet the corresponding elastomers each possess a markedly different nanoscale morphology and rheology in the bulk. We are able to correlate small variations of the binding constant of the end-groups with dramatic changes in the bulk properties of the elastomers. These results provide an important insight into the way in which weak non-covalent interactions can be utilized to afford a range of self-assembled polyurethane based materials that feature different morphologies.

Soluble. branched (meth)acrylic copolymers have been synthesised via facile, one-step, batch solution polymerisations taken to high conversion. Methyl methacrylate has been copolymerised with a number of multifunctional comonomers using a chain transfer agent to prevent gelation. A variety of soluble, branched copolymer architectures have been synthesised using multifunctional monomers containing between two and six acrylate functional groups. Independent of polymer composition, all copolymers were proven to be branched with broader molecular weight distributions compared to linear analogues. The molecular weights, Mark-Houwink constants and T-g's all varied systematically depending on the functionality and concentration of the multifunctional monomer copolymerised. Although the polymer architectures are complex, this methodology is pragmatic, highly practical and very convenient. The need for high control of polymer architecture via controlled radical polymerisation for satisfying applications is questioned. It is proposed that precise control may not be necessary for many applications, whereas new, heterogeneous structures via pragmatic routes may be sufficient and more easily exploited