CHAPTER 13. New Approaches Towards the Design of Tough Amphiphilic Polymeric Co-networks

Since the 1960s, polymer network hydrogels have been used for various applications. However, these applications have been restricted to non-load-bearing ones, due to the inherent mechanical weakness of common hydrogels. This weakness is attributed to the irregular crosslinking density, the high proportion of singly-attached (dangling and, therefore, elastically inactive) chains and the broadly varying distance between crosslinking points. In recent years, ground-breaking studies focusing on the development of novel approaches to fabricate near-ideal polymer network hydrogels with excellent mechanical properties have been developed. In this chapter, these new approaches will be outlined, with specific interest in amphiphilic polymer co-networks (APCNs), i.e. networks containing both hydrophilic and hydrophobic domains. The ability to generate these near-ideal networks, which often also possess ‘smart’ stimuli-responsive properties, would allow APCNs to be used in a wide range of advanced applications, including soft robotics, biomaterials and materials science. These new synthetic methodologies will be described in this chapter and will be separated into either fundamentally altering the network architecture and/or by employing facile and orthogonal coupling chemistries.