Atomic force microscopy studies of molded thin films of segmented polyamides

Abstract

Block copolymers comprise two or more blocks of chemically different monomers. If the blocks are sufficiently large and the interactions between them sufficiently adverse, the blocks will segregate [1, 2]. Since the blocks are inter connected, they can only segregate on a microscopic scale. For example, an AB diblock copolymer with A and B blocks of equal molecular weight will form a mesophase structure of A and B lamellae. The thickness of the lamellae is commensurate with the size of the polymer coil. A particularly interesting type of block copolymer is the ABA triblock copolymer where A constitutes a thermoplastic material (e.g., polystyrene) and B an elastomer (e.g., polybutadiene). Another interesting class of block copolymers is the (AB)n type of copolymers where “A” represents the soft segment and “B” corresponds to the hard block. Segmented polyamides composed of polyether and polyamide structural units is a typical example of (AB)n type block copolymers. Since the structural units are linked via an ester group, such systems are also referred to as polyether – ester – amides [3, 4] having the chain structure as shown below.