A well‐known approach toward mechanochromic polymers relies on the incorporation of excimer‐forming fluorophores into a matrix polymer and the disruption of aggregated chromophores when such materials undergo macroscopic mechanical deformation. However, the required aggregates and stress‐transfer processes have so far only been realized with select dye/polymer combinations. As demonstrated here, the utility of this approach can be extended by tethering an excimer‐forming cyano‐substituted oligo(p‐phenylene vinylene) fluorophore to the two ends of a telechelic poly(ethylene‐co‐butylene) and blending small amounts (0.1–2 wt%) of the resulting aggregachromic macromolecule into polymer matrices such as poly(ε‐caprolactone), poly(isoprene), or poly(styrene‐b‐butadiene‐b‐styrene). All blends display mechanofluorochromic responses, and the ratio between the monomer and excimer emission intensities can be used to correlate the luminescence signal to the extent of deformation and to follow subsequent relaxation processes. The developed approach significantly expands the scope of blend‐based mechanoresponsive luminescent materials.

The stimuli responsiveness of supramolecular polymers has recently been exploited for the development of adhesives that can be (de)bonded on demand when heated or exposed to UV light. However, it remains difficult to combine competitive solid-state mechanical properties and very low melt viscosity in one material. Here we report a new supramolecular polymer adhesives platform based on soybean oil as a multifunctional low-molecular-weight monomer (∼1500 g/mol) and isophthalic acid (IPA) groups that show hydrogen bonding and promote the formation of a reversible network. The polarity difference between the triglyceride backbone and the IPA groups leads to microphase separation, and the crystalline IPA domains act as physical cross-links. Heating the polymer above the melting temperature of the IPA-rich domains results in a dramatic viscosity reduction to 8 Pa•s at 120 °C. Once cooled to room temperature, the material properties are fully recovered as a result of the reassembly of the supramolecular network. Single lap joint adhesive tests performed at room temperature using glass and stainless steel substrates reveal shear strength values of 1.2 and 1.7 MPa, respectively, and heat and UV light can be used as external stimuli to debond on command. In addition, composites were prepared by adding 5 or 10 wt % microcrystalline cellulose (MCC) to the polymer, and this led to an increase of strength and modulus below the glass transition by up to 80% and 170%, respectively. Because the introduction of MCC partially hinders the crystallization of the matrix, the stiffness and tensile strength are reduced above the glass transition, while the elongation at break is significantly increased.

Dynamic and reversible non‐covalent interactions endow synthetic systems and materials with smart adaptive functions that allow them to response to diverse stimuli, interact with external agents, or repair structural defects. Inspired by the outstanding performance and selectivity of DNA in living systems, scientists are increasingly employing Watson−Crick nucleobase pairing to control the structure and properties of self‐assembled materials. Two sets of complementary purine‐pyrimidine pairs (guanine:cytosine and adenine:thymine(uracil)) are available that provide selective and directional H‐bonding interactions, present multiple metal‐coordination sites, and exhibit rich redox chemistry. In this review, we highlight several recent examples that profit from these features and employ nucleobase interactions in functional systems and materials, covering the fields of energy/electron transfer, charge transport, adaptive nanoparticles, porous materials, macromolecule self‐assembly, or polymeric materials with adhesive or self‐healing ability.

A simple and economic method is presented that allows the preparation of transparent polystyrene (PS) substrates activated with chlorosulfonyl groups. Chlorosulfonation has been analyzed by ATR-FTIR. Linear PS chains with different degrees of chlorosulfonation have been synthesized as model compounds in order to analyze the modification quantitatively. After chlorosulfonation the activated surfaces can be quantitatively converted in aqueous solution at room temperature to sulfo or sulfonazide groups or react with bifunctional aliphatic amines of different length via formation of sulfonamide linkages. In this way, surfaces with a huge variety of functionalities like amines, carboxylic or sulfonic groups, sulfonazides, esters, etc. may be obtained in a selective way controlling their density at the surface. In all cases, functional surfaces with excellent optical transparency are obtained. Aminated surfaces have successfully been probed for ELISA assays.

In this work the activation of transparent PS substrates by chlorosulfonation is described and their distribution in the subsurface region is analyzed. For this purpose XPS, FTIR-ATR and colorimetry have been used. It is shown that the electrophilic aromatic substitution of polystyrene in pure chlorosulfonic acid is extremely quick with complete surface coverage by chlorosulfonic groups achieved after only a 10 minute reaction time at -10 °C. It is further demonstrated that the reaction is very surface selective and that even after reaction times as long as 3 hours, the modification is limited to a layer with a thickness of less than one micron. The activated PS substrates can be further functionalized in a second step with carboxylic groups. Due to the excellent optical transparency that the samples maintain upon modification, the modified systems were successfully probed for use in ELISA assays.

The synthesis via copper(I)-catalyzed azide alkyne cycloaddition (CuAAC) of three new monomer derivatives of Nvinyl-2-pyrrolidone (VP) carrying cyclic pyrrolidine, piperidine, and piperazine groups and the corresponding copolymers with unmodified VP is shown. The systems bearing pyrrolidine and piperidine displayed both thermo-and pH-response, which has not been reported previously for a polymer with polyvinylpyrrolidone (PVP) backbone. A broad modulation of the LCST with the copolymer composition and pH was observed in a temperature range 0-100 8C. The polymers carrying piperazine exhibited broad buffering regions and no thermosensitivity.

aIn the present paper, we describe the synthesis of novel monomers prepared by regioselective Michael addition to asymmetric divinylic compounds. This chemoselectivity was experimentally studied employing different reaction conditions and theoretically calculated using chemical global and local descriptors. The global reactivity data show that incoming nucleophilic secondary amines preferentially attack the acrylic derived units acrylate and acrylamide, while deactivated methacrylate and N-vinyl-pyrrolidone require harder reaction conditions, which leads to the formation of by-products. Moreover, it is demonstrated that the presence of two vinyl units within a studied divinylic agent leads to a significant increase in its global reactivity parameters.Besides, the local reactivity parameters of asymmetric divinyl compounds show a preference for an attack at the C b of activated units compared to the C b center of deactivated units. Based on these results, asymmetric divinyl compounds are very interesting starting materials for the preparation of new functionalized monomers.

Proline may work efficiently in water as catalyst of aldol reactions if it is hydrophobically activated. In this work, we have maximized this hydrophobic activation by the preparation of linear alternating copolymers of hydrophobic phenylmaleimide and a vinylpyrrolidone derivative bearing proline. These copolymers were water soluble above pH 5.0 and, unlike the free proline, exhibited efficient catalysis at pH 7.0. Moreover, they catalyzed and presented enantioselectivity in an aggregated form at pH 4.0 (close to the isoelectric point, IEP, of the polymer). This enantioselectivity has been related to the exclusion of water at this IEP. To control the size and stabilize the aggregates, PEG grafted copolymers were prepared by the incorporation of a PEG-macromer (2-10 mol%), which rendered stable nano-aggregates in water at the IEP. At this pH they catalyzed the aldol reaction in a higher rate than the non-grafted polymer, but the enantioselectivity was decreased.