Competitive Adsorption of a Monoclonal Antibody and Nonionic Surfactant at the PDMS/Water Interface.

Interfacial adsorption of monoclonal antibodies (mAbs) can cause structural deformation and induce undesired aggregation and precipitation. Nonionic surfactants are often added to reduce interfacial adsorption of mAbs which may occur during manufacturing, storage, and/or administration. As mAbs are commonly manufactured into ready-to-use syringes coated with silicone oil to improve lubrication, it is important to understand how an mAb, nonionic surfactant, and silicone oil interact at the oil/water interface. In this work, we have coated a polydimethylsiloxane (PDMS) nanofilm onto an optically flat silicon substrate to facilitate the measurements of adsorption of a model mAb, COE-3, and a commercial nonionic surfactant, polysorbate 80 (PS-80), at the siliconized PDMS/water interface using spectroscopic ellipsometry and neutron reflection. Compared to the uncoated SiO2 surface (mimicking glass), COE-3 adsorption to the PDMS surface was substantially reduced, and the adsorbed layer was characterized by the dense but thin inner layer of 16 Å and an outer diffuse layer of 20 Å, indicating structural deformation. When PS-80 was exposed to the pre-adsorbed COE-3 surface, it removed 60 wt % of COE-3 and formed a co-adsorbed layer with a similar total thickness of 36 Å. When PS-80 was injected first or as a mixture with COE-3, it completely prevented COE-3 adsorption. These findings reveal the hydrophobic nature of the PDMS surface and confirm the inhibitory role of the nonionic surfactant in preventing COE-3 adsorption at the PDMS/water interface.

Self-assembly followed by radical polymerization of ionic liquid for interfacial engineering of black phosphorus nanosheets: Enhancing flame retardancy, toxic gas suppression and mechanical performance of polyurethane.

As one of emerging layered nanomaterials, the potential of black phosphorous nanosheets (BP) for fabricating high performance polymer composites was seriously confined by incompatible interface. Herein, interfacial engineering between BP nanosheets and polyurethane (PU) matrix was rationally designed, where employing polymerized ionic liquid as linking bridge between robust BP nanosheets and soft TPU. The ionic liquid (IL) was firstly confined onto the surface of BP nanosheets with the combination of electrostatic-driving self-assembly process and in situ radical polymerization was then performed. The successful preparation of IL-functionalized BP (IL-BP) nanosheets was confirmed by a series of analytic methods, incluing TEM, XPS, FTIR, and so on. The resultant IL-BP nanosheets imparted well mechanical performance and flame retardancy to TPU composites. Compared to the mechanical enhancement reported by other literatures, the break strength of TPU/IL-BP-1.0 was significantly increased by 50%, attributing to strong interfacial regulation of polymerized IL and mechanically robust BP nanosheets, generated by the similar polarity. Meanwhile, significant decreases of 38.2% and 19.7% in peak values of heat release rate and total heat release were achieved for TPU/IL-BP-2.0. With the investigation of combustion residue and pyrolysis products, it was found that a mass of pyrolysis products reacted with IL-BP nanosheets to form mechanically robust protective char and solid products, being no longer used as fuel to support combustion. Meanwhile, the maximum concentration of CO2 and highly toxic CO of TPU/IL-BP-2.0 were effectively decreased by 36.9% and 26.5%, compared to the pure TPU. Such a design route effectively regulates the interfacial interaction between BP nanosheets and polymer matrix and offers a practical route for preparing high performance materials.