Almost ten years ago, Lee et al. [13] formulated a universal adhesive coating based on observation of the strong attachment by mussels through their byssal threads to virtually all types of inorganic and organic surfaces. The amino acid compositions of the mussel foot proteins that generate the attachment are rich in catechol and amine groups. [13][14][15] These groups associate under marine conditions, forming strong covalent and noncovalent interactions with substrates. [13] This led to the idea that both catechol and amine groups were crucial in forming robust, wide spectrum adhesive nanolayers [16,17] and consequently dopamine was conceived as a powerful building block for spontaneous deposition of thin polymer films. The dopamine monomer is deposited onto unadulterated surfaces through self-assembly and oxidative cross-linking from mild pH aqueous solution in a rapid reaction. This results in a durable, nanoscale, conformal, and hydrophilic coating that can be readily modified to introduce specific surface chemistries for a particular application. [18][19][20][21][22] These bioinspired, polydopamine materials are chemically and structurally indistinguishable from eumelanins found in the human body, [23,24] providing excellent biocompatibility. Additionally, polydopamine has broad electromagnetic absorption and excellent photothermal energy conversion [25] as well as having ionic-electronic hybrid conductivity. [26] Along with the excellent coating performance, these properties provide a vast array of potential applications for polydopamine materials.In this article, we explain what is known about polydopamine and related catecholamine coatings; their formation, the adhesion mechanism, and their physicochemical properties and we also review the applications of these materials (Figure 1). Since 2011, there have been a number of reviews on this subject matter, including general reviews on the physicochemical properties of polydopamine coatings [11,20,[27][28][29] and their applications. [20,27,30] There are also a number of more specific reviews on the chemical synthesis and modulation of polycatecholamine coatings, [31] the biomedical applications of these coatings, [8,[32][33][34] their electronic properties, [26,35] the use of polydopamine to make films at fluid interfaces, [36] in hierarchically constructed particles, [33] and capsules, [30] exploitation of polycatecholamine coatings in membrane filtration, [37] polydopamine-derived carbon materials, [38] and the use of coordination chemistry in catechol-based materials. [39] Nonetheless, this area of research is growing so rapidly [25,27] that many recent Polydopamine and related polycatecholamines can be easily deposited onto almost any surface from mild, aqueous solution. This results in durable, nanoscale coatings that exhibit high biocompatibility and have useful chemical and electronic properties. Additionally, these materials can be readily chemically and physically modified, and consequently, they are used extensively for surface modification. This ...

A homologous series of PEG (various chain length)-substituted octasilsesquioxanes were prepared by the hydrosilylation of unsaturated PEGs (poly(ethylene glycol)s) with both octa(dimethylsiloxy)silsesquioxane (Q 8 M 8 H ) and octahydridosilsesquioxane (T 8 H ). The silsesquioxane-PEGs materials were produced by the initial synthesis of a series of allyl-modified poly(ethylene glycol)s and subsequent attachment to both (Q 8 M 8 H ) and (T 8 H ). The products were chemically characterized by Fourier transform infrared (FTIR) and nuclear magnetic resonance ( 1 H, 13 C, and 29 Si NMR) spectroscopy, and the properties of the allyl PEGs and their POSS hybrids were thermally characterized by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The attachment of the PEGs onto the POSS macromonomers (Q 8 M 8 H and T 8 H ) clearly demonstrated a chainlength-dependent increase in T g and a concomitant suppression of crystallization.

A series of POSS (PEG)n)2-6 macromonomers were further functionalized by reaction with methacryloyl chloride and then polymerized with methyl methacrylate to produce a series of hybrid materials where the amounts of POSS (PEG)n)2-6 used as cross-linkers varied from 0.1 to 0.5 mol %. Thermal investigations using TGA and DSC techniques revealed that both POSS concentrations and PEG chain length play important roles in defining structure-property relationships. Incorporation of POSS always increased thermal stability. Although the POSS is a bulky and multifunctional cross-linker, glass transitions did not always increase. In some instances bulkiness of the group created free volume and chain separation, which led to a reduction in the glass transition temperature.