Surfaces and interfaces are the regions through which materials interact with their environment. Thin interfacial polymer layers are often key elements to tailor the surface properties and functionality of devices. In turn, polymer structure, organization at interfaces, stiffness, permeability for small molecules or interaction with biological ligands generally dominate the surface properties. The rapid development of modern highly sensitive analytical and sensing techniques for the interfacial characterization enables us today to unravel the structural features and dynamic aspects of functional polymers at interfaces and to understand how this translates into (bio)performance. The main objective of this project is an attempt to address the complex structure-property relationships of selected, partly novel polymers at surfaces and interfaces. In a field as diverse as this, success largely depends on a transdisciplinary approach combining different expertise and knowledge. Therefore, we propose, in a highly collaborative and concerted effort, to synthesize and investigate a selected number of engineered polymer systems for the (bio)functionalization of surfaces, combining the highly complementary expertise and infrastructure of the three proposing Swiss groups (Meier, Schlüter, Textor groups) in the field of polymer and surface technologies with the theoretical modeling expertise of our Russian partners (Bishtein and Zhulina groups).

To this end, we will develop and test novel biofunctional polymeric thin layers made of linear, dendritic and amphiphilic triblock polymers, with a focus on cost-effective, aqueous self-assembly, “grafting-to” approaches, exploiting biomimetic, DOPA-related and multivalent strong (wet) adhesion. Each type of polymer architectures will be thoroughly characterized using a variety of bulk and surface-analytical techniques and the assembly dynamics studied by complementary in situ sensing methods, The experimental, quantitative results obtained will be used for comparative modeling studies. Preliminary results of a recent feasibility study demonstrated that all three proposed polymer architectures possess different, highly functional properties. Thus, linear PEG and PMOXA hydrophilic polymer chains grafted to the surface have high degree of hydration and flexibility while dendritic PEG macromolecules form thin and comparatively rigid monolayers, and amphiphilic PMOXA- and PEG-PDMS block copolymers self-assemble into supported membranes where interchain interactions determine density, order and fluidity of the layer. Further parameters such as packing density and conformation of the polymer chains, resistance to unspecific protein adsorption (“non-fouling” properties). End-group availability and degree of presentation of biological ligands, density profiles, and functionality of membrane proteins in the polymeric host will be analyzed in both experimental and theoretical studies. First, we will assemble the different polymers on flat 2D substrates, and then use the optimized polymer systems for the functionalization of <10 nm particles. The proposed research will build upon an already established, successful partnership between the Swiss and with the Russian institutions. Our project consortium expects to make an important experimental and theoretical contribution to the field of structure-property relationships for engineered polymer architectures at the material-biology interface thus improving the current knowledge regarding quantitative and nanoscale design rules for the fabrication of biofunctional materials and surfaces, both in 2D (flat surfaces) and 3D (nanoparticles).