Stimulus-Responsive Interfacial Chemistry in CNT/Polymer Nanocomposites

The enhancement of interfacial interactions in carbon nanotube (CNT)/polydimethylsiloxane (PDMS) polymer matrix composites was investigated. The approach taken was to functionalize the CNTs with the photoreactive molecule benzophenone in order to anchor the CNTs to the polymer chains on demand. The anchoring reaction was activated by the use of externally applied UV irradiation. A comparison was done on randomly dispersed and aligned CNTs in order to observe the effect of orientation on interface mechanics and overall enhancement. The effect of interfacial interaction on the mechanical response was determined through analysis of static mechanical experiments, as an increase in interfacial interaction resulted in an observable change in elastic modulus and yield stress. An increase of 22% in elastic modulus was observed in randomly oriented CNTs while an increase of 93% was observed in aligned CNT composites after exposure to UV light. In addition, alignment of CNTs lead to a more discreet yield stress which allowed for a clearer identification of the onset of interfacial failure. This work provides insight into the intelligent design of composites, starting at the nanoscale, to provide desired on-demand macroscale response.