title: The Template Determines Whether Chemically Identical Nanoparticle Scaffolds Show Elastic Recovery or Plastic Failure.
abstract: Subtle variations in the preparation of ice-templated nanoparticle assemblies yield monoliths that are chemically identical but exhibit qualitatively different mechanical behavior. We ice template aqueous dispersions to prepare macroporous monoliths largely comprising silica nanoparticles held together by a crosslinked polymer mesh. When the polymer is crosslinked in the presence of ice crystals, we obtain an elastic sponge that is capable of recovery after imposition of large compressive strains (up to 80%). If, however, the ice is lyophilized before the polymer is crosslinked, we obtain a plastic monolith that fails even for modest strains (less than 10%). The elastic sponge and the plastic monolith are chemically identical; they have the same organic content, the same ratio of polymer to crosslinker, and the same average crosslink density. Atomic force microscopy (AFM) was used to probe the local mechanical properties of the crosslinked polymer mesh. These measurements indicate that plastic monoliths dissipate significantly more energy and have a larger spatial variation in local mechanical response relative to the elastic sponges. We believe that this behavior might correlate with a wider spatial distribution of crosslinks in plastic scaffolds relative to elastic scaffolds.
authors.affiliation: J-101, Polymers and Advanced Materials Laboratory, Complex Fluids and Polymer Engineering, Polymer Science and Engineering Division, CSIR-National Chemical Laboratory , Pune 411008, Maharashtra, India.
authors.forename: Karthika
authors.initials: K
authors.lastname: Suresh
authors.affiliation: Department of Physics, Indian Institute of Science Education and Research , Pune 411008, India.
authors.forename: Shivprasad
authors.initials: S
authors.lastname: Patil
authors.affiliation: J-101, Polymers and Advanced Materials Laboratory, Complex Fluids and Polymer Engineering, Polymer Science and Engineering Division, CSIR-National Chemical Laboratory , Pune 411008, Maharashtra, India.
authors.forename: Pattuparambil
authors.initials: P
authors.lastname: Ramanpillai Rajamohanan
authors.affiliation: J-101, Polymers and Advanced Materials Laboratory, Complex Fluids and Polymer Engineering, Polymer Science and Engineering Division, CSIR-National Chemical Laboratory , Pune 411008, Maharashtra, India.
authors.forename: Guruswamy
authors.initials: G
authors.lastname: Kumaraswamy