In situ AFM observations show that when PILP droplets contact a surface, their initial properties are either a liquid with a high interfacial tension (350 mJ m-2) or a soft gel-like material with a low modulus (less than 0.2 MPa). These findings suggest that PILP may initially be liquid-like to infiltrate collagen fibrils, enabling the production of interpenetrating composites, and/or become viscoelastic, to provide a means for moulding minerals.