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5 figures.-- Supplementary information available., Heterostructures of two-dimensional (2D) materials using graphene and MoS2 have enabled both pivotal fundamental studies and unprecedented sensing properties. These heterosystems are intriguing when graphene and MoS2 are interfaced with 2D sheets that emulate biomolecules, such as amino-terminated oligoglycine self-assemblies (known as tectomers). The adsorption of tectomer sheets over graphene and MoS2 modulates the physicochemical properties through electronic charge migration and mechanical stress transfer. Here, we present a systematic study by Raman spectroscopy and tectomer-functionalised scanning probe microscopy to understand mechanical strain, charge transfer and binding affinity in tectomer/graphene and tectomer/MoS2 hybrid structures. Raman mapping reveals distinctive thickness dependence of tectomer-induced charge transfer to MoS2, showing p-doping on monolayer MoS2 and n-doping on multilayer MoS2. By contrast, graphene is n-doped by tectomer independently of layer number, as confirmed by x-ray photoelectron spectroscopy. The interfacial adhesion between the amino groups and 2D materials are further explored using tectomer-functionalised probe microscopy. It is demonstrated here that these probes have potential for chemically sensitive imaging of 2D materials, which will be useful for mapping chemically distinct domains of surfaces and the number of layers. The facile tectomer-coating approach described here is an attractive soft-chemistry strategy for high-density amine-functionalisation of atomic force microscopy probes, therefore opening promising avenues for sensor applications., We would like to acknowledge strategic development funding from the University of Sussex. Additional funding from the Aragon Government is also acknowledged (Grupo de Nanosensores y Sistemas Bioanalíticos (N&SB), ref. E25_20R). [...] This work was also partially supported by a UKRI Future Leaders Fellowship (Grant No. MR/T042664/1).

Work presented at the International Biodeterioration & Biodegradation Symposium (IBBS18), 6-9 September 2021 | Online conference, The atomically thin 2D materials have unique physicochemical properties useful for sensing applications in chemical, biological and corrosion science.1, 2 The high surface-to-volume ratio of these layered materials facilitates efficient response due to the ultrafast carrier mobility of surface atoms. These surface atoms form physiosorbed bonds with adsorbed analyte through electrostatic interactions that can be envisioned in terms of locally induced strain (%) and charge redistribution (n) compared to its pristine state.3 The non-covalent interaction between the analyte and 2D materials shift the Fermi energy level of the host, useful for the selectivity as it offers unique ‘figureprints’ in the optical spectrum. Here, I will present an overview of a systematic study of surface analysis techniques, in particular, using scanning probe microscopy and Raman spectroscopy to uncover physical strain and doping in different 2D materials of graphene and MoS2 for physio-adsorption of analytes. The present study strengthens the possibility of sensing the interaction between several organic and biomolecules toward different 2D materials which is essential in biological and polymeric systems.

1 figure.-- Talk delivered at the SmallChem 2021 International online conference (17th-18th february 2021)., Amino-terminated oligoglycines non-covalently self-assemble, through cooperative hydrogen bonding formation, into biocompatible rigid 2D nanostructures called tectomers, either in solution or in surfacepromoted processes. Tectomers effectively coat carboxylated multi-walled carbon nanotubes (MWCNT-COOH) and strongly interact with graphene oxide (GO). Electrostatic interactions and hydrogen bonding formation accounts for the strong interfacial interaction of tectomers with MWCNTCOOH and GO, respectively. The resulting composites were characterized by electron- and atomic force microscopies, UV-vis and X-ray photoelectron (XPS) spectroscopies and contact angle measurements. Because of this high affinity of tectomers to GO, tectomers efficiently coat wet-spun GO fibers (Fig. 1). We also show that, due to their versatile surface chemistry, tectomers act as supramolecular peptidic adhesives for the immobilization of a variety of carbon nanomaterials, nanoparticles, molecules and drugs on the GO fiber surface therefore allowing GO fiber functionalization. The resulting ultrathin coatings exhibit remarkable water-resistant properties. This tectomer-based “double-sided sticky tape” fiber functionalization strategy can be extended to other fibers, fabrics and substrates, making it very attractive for technological and smart textile applications

Work presented at the nano Portugal 2020 Online Conference (nanoPT2020), Nanoscience and Nanotechnology International Conference, 23th - 24th september 2020., Amino-terminated oligoglycines non-covalently self-assemble, through cooperative hydrogen bonding formation, into biocompatible rigid 2D nanostructures called tectomers. Tectomers effectively coat carboxylated multi-walled carbon nanotubes (MWCNT-COOH) and strongly interact with graphene oxide (GO). Electrostatic interactions and hydrogen bonding formation accounts for the strong interfacial interaction of tectomers with MWCNT-COOH and GO, respectively. Because of the high affinity of tectomers to GO, tectomers have been used to coat wet-spun GO fibers. We here show that, due to their versatile surface chemistry, tectomers act as supramolecular adhesives for nanomaterial and molecule immobilization on the GO fiber surface. Tectomer-coated GO fibers can then be subsequently decorated with a variety of carbon nanomaterials (carbon nanotubes, carbon nanohorns, carbon nanocones, and highly fluorescent nanodiamonds), metal (gold, platinum, iron) nanoparticles, acrylate-based polymer nanoparticles, fluorophores and drugs. The resulting ultrathin coatings exhibit remarkable water resistant properties. We show that this tectomer-based “double-sided sticky tape” fiber functionalization strategy can be extended to other fibers and fabrics, such as polyurethane/PEDOT:PSS, poly(methyl methacrylate) and polyester, making it very attractive for a variety of technological and smart textile applications.

16 Figuras.-- Información suplementaria disponible en línea en la página web del editor.-- © 2019. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/, Amino-terminated oligoglycine two-dimensional (2D) peptide self-assemblies (known as tectomers) have a versatile surface chemistry that allows them to interact with a variety of nanomaterials and to actas supramolecular adhesives for surface functionalization. Here, we have exploited the strong hydrogen-bond based interaction between tectomers and graphene oxide (GO) to functionalize GO fiber surfaces with different carbon nanomaterials (carbon nanotubes, carbon nanohorns, carbon nanocones, and highly fluorescent nanodiamonds), metal (gold, platinum, iron) nanoparticles, acrylate-based polymernanoparticles, fluorophores and drugs. The resulting ultrathin coatings exhibit remarkable water resis-tant properties. This tectomer-mediated fiber decoration strategy allows coating functionalities to be tailored by choosing the appropriate nanomaterials or other molecules. We show that this strategy can be extended to other fibers and fabrics, such as polyurethane/PEDOT:PSS, poly(methyl methacrylate) and polyester, making it very attractive for a variety of technological and smart textile applications., Authors thank the Fundación Domingo Martínez (Ayudas a la Investigación 2013) and Diputación General de Aragón (Grupo de Nanosensores y Sistemas Bioanalíticos (N&SB), ref. E25_17R) for research funding. MT would like to acknowledge University of Sussex strategic development fund. JMR acknowledges funding from the Australian Research Council (DP170102859).