The ability to detect early damage is of great significance in load bearing composite materials used for high performance applications. Microdamages if left unchecked can grow under subsequent stress, leading to catastrophic structural failure. The sensing of early stage damage via nondestructive methods is therefore critically important for the safe use of these materials. Herein a supramolecular approach to self-diagnosis of early stage damage in a carbon fiber epoxy composite material, via the incorporation of a CB[8] based ternary complex as an additive is reported. The complex comprising a fluorescent probe and a quencher encapsulated by the CB[8] is introduced into the epoxy resin of the composite as a supramolecular cross-linking agent, whose stress-induced dissociation results in the turn on of fluorescence of the probe. In this way, detection of irreversible mechanical strain and fatigue at an early stage is attainable, enabling the assessment of microdamage in the material.

Advanced applications, involving high risk mechanical systems, require the in-service deformation level to be verified in order to assess their safety and reliability, providing information for repairing or replacing interventions. In the present work, a self-diagnostic poly(dimethylsiloxane) (PDMS) elastomer containing a supramolecular detection probe is proposed, enabling the strain intensity in the polymeric matrix to be identified by fluorescence detection. Turn-on fluorescence represents an efficient, sensitive, simple, and real time diagnostic tool to quantitatively detect high-strain regions for the mechanical monitoring of structural elements. The supramolecular complexcross-linking the polymer's chainsprovides fluorescence response induced by strain even if present in a very low amount (10 −6 mol kg −1 ), completely preserving the mechanical characteristics of the matrix. The developed PDMS material is mechanically tested, and the observed fluorescence field is correlated with that obtained by theoretical and numerical simulations as well as by contactless measurements performed via the digital image correlation (DIC) technique.

Controlled phase separation in a polymer film, with subsequent morphology rearrangement on the micro-scale, provides novel perspectives in smart materials. Based on our experience on supramolecularly compatibilised polymer blends consisting of polystyrene and poly(butyl methacrylate), we demonstrate here physical segregation of the blend in the solid state by the application of an electrochemical stimulus. The thereby occurring changes in film morphology, namely the appearance of voids and grains, have been characterised by atomic force microscopy in spin coated and in Langmuir-Schaefer deposited films.

The properties of low band gap polymers in devices such as solar cells are strongly influenced by their morphology and ability of self-organization in thin films and interface properties. We study the influence of alkyl and alkoxy side chain position for four conjugated, alternating oligothiophene-benzothiadiazole copolymers on the molecular orientation in thin films and electronic interface properties using photoemission, X-ray absorption spectroscopy (XAS) at the sulfur K edge, and polarization modulation-infrared reflection–absorption spectroscopy (PMIRRAS). The interface charge transfer (ICT) model is used to explain interface properties of the polymers on substrates with different work functions. We find that the position of the side chains has a significant influence on the orientation and thus on self-organization properties of the polymers in thin films, whereas the electronic structure is less affected. The preferred molecular orientation is further affected by annealing, leading to a higher degree of ordering. Results from complementary methods with different surface sensitivities (XAS in total electron yield and fluorescence mode and PMIRRAS) are discussed.

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