A combination of electrospray ionization (ESI) and ion mobility mass spectrometry (IMMS) is used to successfully determine the characteristic ratio (Cn) of homopolymers and triblock copolymers. Two different copolymer systems are analyzed: a poly(ethylene glycol)/poly(propylene glycol) (PEG/PPG) and a poly(methyl acrylate)/poly(butyl acrylate) (PMA/PBA) based system. The monomer composition within the copolymers is chosen to be constant while changing the block sequence along the main chain, in order to ensure a reliable determination of the influence of the topology on the physical properties. It can be demonstrated that the block structure has a significant influence on Cn and therefore on the physical properties of the block copolymers. For both systems, the inner block dominates the overall physical properties.
Introduction
Polymers in modern applicationsEven though polymer science as a field of research is still quite young when compared to early organic or inorganic chemistry, it has quickly permeated all aspects of modern life. Polymers are now ubiquitous in industrial processes, consumer electronics, tires, foam rubbers and many other application that are integral to modern society. 1 While a lot of these processes and products rely on relatively simple homo polymers, increasingly complex applications, like drug-delivery systems, sensors and other nanotechnological applications or self-assembly systems, give rise to the need for more and more intricately designed polymers. 2 These include systems such as block copolymers, polymers with specific topologies like cyclic or star-shaped polymers, nanocomposites, polymer membranes, microstructured systems or surface-grafted polymers. [2][3][4] The synthesis of these precisely tailored polymers in turn depends on new * The derivations given in this section were adapted and in parts updated based on the work of Kokubo. 36
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