Specifically selected peptide–polymer conjugates, applied for inorganic–organic interface compatibilization, lead to stiffer and tougher materials. The concept is based on the sequence‐specific interaction of a peptide with inorganic surfaces and utilizes the idea of interface management of natural materials such as bone and nacre where proteins mediate inorganic–organic interactions.

Peptide-polymer conjugates are applied as interface stabilizers that are precisely tuned to recognize the surfaces of inorganic constituents in composites. A set of peptide sequences is usually selected through phage-display and a strategy is presented for the identification of the most effective sequences through the evaluation of secondary interactions, including not only surface binding but also solubility and self-aggregation tendency.

In this study, a bio-inspired hybrid material is investigated by in situ X-ray scattering experiments in combination with mechanical tensile testing. The material is composed of nanometer-sized spherical magnesium fluoride particles which are linked via material-specific peptide poly(ethylene glycol)-PEG conjugates to a semi-crystalline poly(ethylene oxide) PEO matrix. Mechanically relevant changes in crystal size and orientation in the PEO matrix are followed by wide angle X-ray scattering during the application of tensile stress. The amorphous phase of PEO is stabilized by the surfaceengineered MgF 2 nanoparticles, leading to increased Young's modulus and tensile strength. Furthermore, small angle X-ray scattering experiments allowed the identification of a layer on the MgF 2 particle surfaces, which increases in thickness with the conjugate amount and leads to suppression of the agglomeration of MgF 2 nanoparticles. In conclusion, the use of selected peptide-PEG conjugates tailored to link MgF 2 particles to a PEO matrix successfully mimics the biological principle of interface polymers and suggests new directions for material fabrication for bio-applications.

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