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Suzuki-Miyaura polycondensation (SPC) is widely used to prepare a variety of copolymers for a broad range of applications. Although SPC protocols are often used in many instances, the limits of this method and issues of molecular weight reproducibility are not often looked at in detail. By using a spiropyran-based (SP) mechanochromic copolymer, we present an optimized protocol for the microwave-assisted synthesis of a mechanochromic, alternating copolymer P(SP-alt-C-10) via SPC that allows the reproduction of molecular weight distributions. Several parameters such as microwave power, temperature, stoichiometry, and ligand are screened, leading to molecular weights up to M-w similar to 174 kg mol(-1). The process of optimization is guided by NMR end group analysis which shows that dehalogenation, oxidative deborylation and SP cleavage are the limiting factors that impede further increase of molar mass, while other classical side reactions such as protiodeborylation are not observed. Embossing films of P(SP-alt-C-10) yields the colored merocyanine (MC) copolymer P(MC-alt-C-10) that undergoes a thermally facilitated back reaction to P(SP-alt-C-10). DFT suggests that the barrier of the SP -> MC transition has two contributions, with the first one being related to the color change and the second one to internal bond reorganizations. The barrier height is 1.5 eV, which suggests that the ease of the thermally facilitated back reaction is either due to residual energy stored in the deformed polymer matrix, or arises from an MC isomer that is not in the thermodynamically most stable state

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The surfaces of many organisms are covered with hairs, which are essential for their survival in a complex environment. The generation of artificial hairy surfaces from polymer materials has proven to be challenging as it requires the generation of structures with very high aspect ratios (AR). We report on a technique for the fabrication of surfaces covered with dense layers of very high AR nanoscale polymer hairs. To this, templates having pores with diameters of several hundred nanometers are filled with a polymer melt by capillary action. The polymer is then allowed to cool and the template is mechanically removed. Depending on the conditions employed, the formed structures can be a simple replica of the pore, or the polymer is deformed very strongly by cold drawing to yield in long hairs, with hair densities significantly up to 6,6 × 108 hairs/cm2 at AR of much higher than 200. The mechanism of hair formation is attributed to a delicate balance between the adhesion forces of the polymer in the pore and the yield force acting on it during mechanically demolding. We demonstrate how with very little effort and within a timescale of seconds unique topographies can be obtained, which can dramatically tailor the wetting properties of common polymers.