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Vitrimers are polymer networks in which associative exchange reactions can take place under specific conditions, thus conferring reprocessability to insoluble materials. Recently, catalyst-free vitrimers have emerged as a new generation of vitrimers able to overcome potential leaching, aging, and sintering issues of catalysts and to ensure the preservation of vitrimer properties after numerous reshaping processes. Here, a catalyst-free epoxy vitrimer featuring α-CF3-substituted ester functions is reported. First, a new tetra-acid precursor was synthesized via a catalyst-free thia-Michael addition. A catalyst-free ring-opening polymerization was then performed on two different diepoxy monomers (DGEBA and BDGE) to obtain polymer networks composed of ester linkages. Curing was evaluated by rheology, differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR) monitoring of the polymerization kinetics. A gel content of over 70% was measured after 24 h in tetrahydrofuran (THF). Finally, the accelerating effect of the α-CF3group on transesterification reactions was highlighted by stress-relaxation experiments and analyzed computationally on a molecular model system. Reprocessability tests were carried out at 150 °C for 2 h. The mechanical and thermal properties of the reshaped materials were similar to those of the initial ones. This study demonstrates the potential of fluorinated groups as powerful internal activators for transesterification vitrimers.

Perfluoropolyalkylethers (PFPAEs) are a class of fluorinated polymers having −OCF2–, −OCF2CF2–, and −OCF2CF(CF3)– as common chain units. The ether linkages distinguish them from other famous fluorinated polymers such as poly(tetrafluoroethylene). Their higher mobility highlighted by below zero glass transition temperatures permit them to be noncrystalline, which makes them easy to use for many applications. They possess interesting tribological properties, combined with an excellent thermal and chemical stability, make them very useful as lubricants. However, after chemical modifications, they also demonstrated to be very useful in numerous applications as surfactants, electrolytes, high performance coatings, vitrimers, or microfluidic devices, to give a few examples. This Perspective aims to summarize all the chemical modifications reported on these PFPAEs to provide a new insight into their potential utility in emerging fields. Indeed, the end group can modulate the properties of PFPAE-based materials such as lubricity, superhydrophobicity, biofouling, antibacterial activity, amphiphilicity, and the ability to react further with comonomers under photochemical and thermal processes. It can also modulate their intrinsic properties such as viscosity and solubility in common organic solvents. The chemical modifications are sorted in five main parts: the condensation reactions, the nucleophilic reactions, the click chemistry reactions, the radical reactions, and finally reactions going through other mechanisms or requiring a multistep process. They can be employed as such or for further polymerization processes depending on the targeted application. Examples of applications are thoroughly described to demonstrate their current usefulness and to help provide direction for their future use.

The copolycondensation of siloxane and silane bearing hydrido and methoxy groups, respectively, was carried out in a surfactant-free aqueous emulsion, at room temperature and using B(C6F5)3 as a water‐tolerant Lewis acid. Several characterization techniques, including triple detection SEC, 29Si NMR and MALDI‐TOF, confirmed the generation of linear polymers (no macrocycles), of average molar masses ranging between 30 and 80 000 g · mol−1, and bearing silanol end‐groups. Colloidal evolution with time showed that a stable surfactant‐free emulsion was generated before some coalescence occurs by decreasing the content of silanol groups suspected to stabilize the emulsion. The kinetics of reaction was followed by SEC, and revealed the generation of small cycles, along with linear oligomers, before converting them to poly(dimethylsiloxane) chains. A tentative mechanism, where ring‐opening polymerization of the most stranded cyclosiloxane and polycondensation of polymer chains are considered, is proposed.

Polystyrene-block‐poly(2‐ethylhexanyl acrylate)‐block‐polystyrene triblock copolymers with different molar masses were synthesised by atom transfer radical polymerisation which led to the formation of elastic gels in paraffin oil. Copolymers with control over molecular weight and low polydispersity were first obtained with different midblock lengths (10 000, 20 000, 60 000 g · mol−1). In paraffin oil, some triblock copolymers led to a gelation process due to appropriate chain length and concentration. We assumed that polystyrene endblocks aggregated into micelles whereas poly(2‐ethylhexanyl acrylate) midblocks formed loops or bridges between different micelles leading to the formation of a physical network of interconnected polymer chains. Rheological measurements proved that time and slow controlled cooling improved the elastic properties with the creation of new interactions in the network.

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