Sustainable monomers were designed from itaconic acid and thiolactone. These monomers enabled the preparation of multi-functional polymers according to different pathways.

The influence of the macroRAFT agent architecture on the morphology of the self-assemblies obtained by aqueous RAFT dispersion polymerization in PISA is studied by comparing amphiphilic AC, A(B-co-C) diblocks and ABC triblock copolymers, constituted of N,N-dimethylacrylamide (DMAm = A), acrylic acid (AA = B) and N-cyanomethylacrylamide (CMAm = C) monomer units. The aim of this study is to better understand the impact of the presence of pH-sensitive acrylic acid units and their spatial distribution in block copolymers. Generally, the presence of a fully protonated intermediate block of PAA between the two blocks (based on PDMAm and PCMAm) favors the formation of higher-order morphologies. These ABC triblock copolymers assemblies are pH-responsive and can undergo morphological transitions through the controlled deprotonation or protonation of the PAA segment, but do not completely dissociate at high pH (i.e. when AA units are fully ionized) unlike their A(B-co-C) diblock counterparts, where the pH-responsive monomer unit is homogeneously distributed within the solvophobic block.

The molar fraction and ionization of acrylic acid ( α AA ) in the monomer feed affect the chemical composition, the composition profile and the particle morphology in PISA.

Finding and developing new biosourced materials that can compete with the current petro-sourced ones are a top priority in order to transition to a more sustainable society. Although the preparation of biosourced polyesters or polyamides is quite well described, finding biosourced and sustainable alternatives to petro-sourced polystyrene is still challenging. Herein, we report the synthesis of polystyrenes prepared in three steps from vanillin, 4-hydrobenzaldehyde, and syringaldehyde, compounds that can be obtained through lignin depolymerization under oxidative conditions. The synthesis involves the conversion of these biosourced platforms into polymerizable styrene derivatives through a methylation of the hydroxyl group followed by an olefination of the aldehyde function. The monomers were first synthesized under conventional conditions using solvents. Then, the synthesis was improved from the sustainability point of view by using a ball mill under solventless conditions, generating much less waste in the process. The three monomers were then converted into biosourced homopolymers through free radical polymerization in bulk, providing functional polystyrene derivatives with thermal properties comparable to those of common petro-sourced polystyrene.

Combining organic and inorganic materials is a fascinating strategy to produce hybrid materials that combine the advantages of both polymeric and inorganic materials. Among the various types of organic-inorganic hybrids, stimuli-responsive magnetic polymer hybrids (RMPHs) are particularly promising materials for a wide variety of applications. While the magnetic properties are generally provided by the presence of magnetic nanoparticles, such as iron oxide nanoparticles, the polymeric compound brings the stimuli-responsiveness, e.g. responsiveness to pH, temperature, redox reaction or irradiation. Furthermore, as the chemical structure and architecture of the polymeric materials are diverse and easily tunable, stimuli-RMPHs have found applications in various domains, including catalysis, biotechnology, (bio)imaging and cancer therapy. Given the importance of the hybrids' shape and morphology for the targeted application, this review presents the possible synthetic strategies to rationally design stimuli-RMPHs of various morphologies ranging from nanometric core-shell structures to nanogels, microgels and membranes. (c) 2023 The Authors. Polymer International published by John Wiley & Sons Ltd on behalf of Society of Industrial Chemistry.

Biobased amphiphilic diblock copolymers are prepared by RAFT-mediated emulsion PISA in water from lignin-derived aromatic compounds.

We report the straightforward synthesis of dual stimuli-responsive nano-objects using a RAFT-mediated polymerization-induced self-assembly process in water. The key to complex and tunable responsiveness was the copolymerization of N-cyanomethylacrylamide, providing upper critical solution temperature-type polymers, with a pH-sensitive monomer (acrylic acid, AA). Not only the core block length but also the AA content and slight changes in the degree of ionization of AA in the polymerization medium (alpha AA,0) had a great impact on the particle morphology. Generally, higher AA contents favored the formation of spherical nano-objects, while low alpha AA,0 led to higher-order morphologies. We demonstrated that the nano-objects exhibited a complex dual responsiveness to changes in the degree of ionization and temperature. Progressively increasing post-polymerization the degree of ionization of the AA units incorporated in the copolymer (alpha AA) triggered morphological transitions. Remarkably, a single copolymer composition formed well-defined vesicles, worms, and spheres that eventually dissociated into individual chains. Temperature-dependent small-angle X-ray scattering analyses evidenced a complex thermo-responsive behavior, which depended on the copolymer composition and alpha AA. For some compositions, we observed both a cloud point and a clearing point, attributed to the formation of secondary aggregates and chain dissolution, respectively.

Novel dual thermoresponsive N-cyanoethylacrylamide (CEAm)-based (co)polymers synthesized by RAFT polymerization display a lower critical solution temperature (LCST) and an upper critical solution temperature (UCST) in water.

Functional nanoporous polymeric materials have been prepared from novel polystyrene-block-poly(ethylene oxide) (PS-b-PEO) diblock copolymer precursors containing a reversible boronate ester junction between both blocks. To this purpose, homopolymers presenting either a boronic acid or a (nitro)catechol end functionality were synthesized. The coupling of each homopolymer presenting complementary chemical functions was successfully achieved under mild conditions and allowed for the generation of the corresponding boronate ester-containing diblock copolymers. Upon orientation of these precursors on silicon wafers via solvent vapor annealing, the resulting films were submitted to PEO etching through selective cleavage of the boronate ester junction under mild acidic conditions. SEM micrographs of the as-obtained thin films revealed the generation of 12 nm-diameter oriented cylindrical nanopores perpendicular to the silicon support surface.

In the framework of the development of multi-responsive polymer materials, a well-defined copolymer bearing supramolecular recognition units was designed based on 2-(dimethylamino)ethyl methacrylate (DMAEMA) and a dialkoxynaphthalene-functionalized monomer (NaphtA). The supramolecular host-guest interactions of this P (DMAEMA-co-NaphtA) copolymer with the electron-deficient CBPQT(4+), 4Cl(-) cyclophane host were studied by H-1 NMR spectroscopy, UV-Visible spectroscopy and isothermal titration calorimetry (ITC), revealing, a high association constant of 6.5 x 10(5) M-1 in water. The addition of CBPQT(4+), 4Cl(-) to a colorless solution of the copolymer in water resulted in a purple solution due to the formation of donor-acceptor inclusion complexes, the intensity being directly proportional to the amount of host added. Investigations on the thermoresponsive behavior of the naphthalene-functionalized copolymer highlighted that the cloud point temperature is directly proportional to the amount of CBPQT(4+), 4Cl(-) host added and can simply be programmed within a temperature window from 30 degrees C to 48 degrees C by playing with pH. The dethreading process was studied as function of temperature and anionic exchange of the counterions of the CBPQT(4+), 4Cl(-). Interestingly, a partial decomplexation was observed by heating the sample above the cloud point temperature while a complete and programmable dethreading was achieved by adding the anionic surfactant sodium dodecyl sulfate (SDS) as a competitive counterion of the host molecule.

In this present work, the synthesis of a new family of upper critical solution temperature (UCST)-thermoresponsive polymers based on N-cyanomethylacrylamide (CMAm) is reported. It is demonstrated that the thermally initiated reversible addition fragmentation chain transfer (RAFT) polymerization of CMAm conducted in N,N-dimethylformamide (DMF) is well controlled. The homopolymer presents a sharp and reversible UCST-type phase transition in pure water with a very small hysteresis between cooling and heating cycles. It is demonstrated that the cloud point (TCP ) of poly(N-cyanomethylacrylamide) (PCMAm) is strongly molar mass dependent and shifts toward lower temperatures in saline water. Moreover, the transition temperature can be tuned over a large temperature range by copolymerization of CMAm with acrylamide or acrylic acid. The latter copolymers are both thermoresponsive and pH responsive. Interestingly, by this strategy sharp and reversible UCST-type transitions close to physiological temperature can be reached, which makes the copolymers extremely interesting candidates for biomedical applications.

We have previously demonstrated that poly(N-cyanomethylacrylamide) (PCMAm) exhibits a typical upper-critical solution temperature (UCST)-type transition, as long as the molar mass of the polymer is limited, which was made possible through the use of reversible addition-fragmentation chain transfer (RAFT) radical polymerization. In this research article, we use for the first time N-cyanomethylacrylamide (CMAm) in a typical aqueous dispersion polymerization conducted in the presence of poly(N,N-dimethylacrylamide) (PDMAm) macroRAFT agents. After assessing that well-defined PDMAm-b-PCMAm diblock copolymers were formed through this aqueous synthesis pathway, we characterized in depth the colloidal stability, morphology and temperature-responsiveness of the dispersions, notably using cryo-transmission electron microscopy (cryo-TEM), dynamic light scattering (DLS), small angle X-ray scattering (SAXS) and turbidimetry. The combined analyses revealed that stable nanometric spheres, worms and vesicles could be prepared when the PDMAm block was sufficiently long. Concerning the thermoresponsiveness, only diblocks with a PCMAm block of a low degree of polymerization (DPn,PCMAm < 100) exhibited a UCST-type dissolution upon heating at low concentration. In contrast, for higher DPn,PCMAm, the diblock copolymer nano-objects did not disassemble. At sufficiently high temperatures, they rather exhibited a temperature-induced secondary aggregation of primary particles. In summary, we demonstrated that various morphologies of nano-objects could be obtained via a typical polymerization-induced self-assembly (PISA) process using PCMAm as the hydrophobic block. We believe that the development of this aqueous synthesis pathway of novel PCMAm-based thermoresponsive polymers will pave the way towards various applications, notably as thermoresponsive coatings and in the biomedical field.

UCST-type poly(acrylamide-co-acrylonitrile) diblock copolymers synthesized in water (by PISA) can not only undergo reversible temperature-induced chain dissociation, but also temperature-induced morphological transition.

Biobased amphiphilic diblock copolymers are prepared thanks to the combination of reversible addition-fragmentation transfer (RAFT) polymerization and polymerization-induced self-assembly (PISA) in an eco-friendly solvent mixture. First, the formation of a poly(acrylic acid) macroRAFT agent (PAA-TTC) is performed in water at 70 °C. Then, in a series of experiments, the PAA-TTC macroRAFT agent is used directly, without purification, as both chain transfer agent and stabilizing agent in the RAFT-PISA of menthyl acrylate (MnA) in dispersion in an ethanol/water mixture. The polymerizations of MnA are fast with high final conversions and well-controlled amphiphilic diblock copolymers are synthesized. Stable, sub-micrometric spherical particles composed of the diblock copolymers are formed. The influence of the monomer concentration and the length of the solvophobic block on the diameter of the self-assemblies is studied by means of dynamic light scattering and cryogenic transmission electron-microscopy.