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One of the challenges for modelling of polymerization kinetics is the detailed description of the molecular build-up of both linear and non-linear chains, specifically those with many grafts and crosslinks. Such grafted/crosslinked (co)polymers are relevant as emulsifiers, surface-modifying agents, coating materials, and compatibilizers. In the present work, we put forward a coupled matrix-based Monte Carlo (CMMC) concept to be successful in this respect, avoiding computational stiffness. The CMMC concept is illustrated for single phase grafting of polybutadiene (PB) with styrene (St) at 343 K by limiting the St conversion to 30%. Considering literature kinetic parameters, a benchmark for average characteristics as obtainable by deterministic method of moments simulations is first presented to then gradually extend the level of modelling output addressing (i) conventional grafting performance indicators (e.g. the grafting yield and mass ratio); (ii) univariate chain length distributions for all macrospecies types (polystyrene, PB, PB with only T grafts, PB with at least one H graft, etc.); (iii) bivariate St–butadiene distributions showing a compositional drift, due to the kinetic tendency to attack longer chains if they are sufficiently present and the competition between grafting and crosslinking; (iv) the explicit molecular build-up of individual molecules predicting the positioning of the St–Bd and St–St connectivity points and the chain formation history. It is demonstrated that the CMMC tool allows the simulation of the contribution and structure of molecules that are hard to access purely experimentally, so that in the long run, novel structure–property relationships are within reach. It is also showcased that consideration of elementary reactions is highly recommended and that even at 343 K, thermal self-initiation with St and related chain transfer reactions matter for a full appreciation of molecular variations. The current work also opens the pathway to identifying pragmatic equations for the experimentalist and online control benefiting from a detailed CMMC solution under any desired conditions.

A thermo-responsive copolymer with a gas-switchable LCST-type phase transition was synthesized by reversible addition–fragmentation chain transfer (RAFT) polymerization of N-isopropylacrylamide (NIPAM) and glycidyl methacrylate (GMA), followed by post-polymerization functionalization with sodium 3-amino-1,2,4-triazole (ATANa). Incorporating ionic moieties provides an elevated cloud point of 61 °C. Importantly, both CO2 and SO2 cause a reduction in the cloud point of the polymer solution. The CO2-triggered system can be easily and fully recovered to its initial state by introducing an inert gas (e.g. N2), whereas the SO2-triggered system shows only partial recovery. The pH-dependent phase transition behaviors confirm that the gas bubbling-induced pH changes contribute to the gas-switchable cloud point of P(NIPAM-co-(GMA-ATANa)). In addition, P(NIPAM-co-(GMA-ATA)) (ATA: 3-amino-1,2,4-triazole), a counterpart of P(NIPAM-co-(GMA-ATANa)), was prepared and the relevant solution phase transition behavior was studied. Its cloud point shift in response to gas bubbling and pH adjustment is opposite to that of P(NIPAM-co-(GMA-ATANa)), indicating that the latter does not result from the protonation of amidine groups. Alternatively, a reversible H+-induced decrease in hydrophilicity was thus proposed. This contribution enriches the family of thermo-responsive polymers by introducing gas-sensitive polyelectrolytes and also broadens the scope of gas-responsive smart materials.

Photoinduced atom transfer radical polymerization with an Fe catalyst was successfully performed in aqueous media for the first time. Three water-soluble ligands [i.e., tetrabutylammonium bromide (TBABr), tris[2-(2-methoxyethoxy)ethyl]amine (TDA), and triphenylphosphine-3,3′,3′′-trisulfonic acid trisodium (TPPSA)] were screened for polymerization in aqueous media. Linear semilogarithmic plots, increasing molecular weights (Mn) with conversion, and low dispersity (Đ < 1.40) were achieved by using a new water-soluble phosphine ligand TPPSA, indicating a well-controlled polymerization. Subsequently, the polymerization kinetics of different catalyst concentrations and the targeted degree of polymerizations were investigated. The applicability of this system to the polymerization of different water-soluble monomers was examined. Furthermore, the polymerization can be regulated by switching the light on and off, which further confirmed its controlled and “living” nature. A successful experiment of chain extension suggested the retention of chain-end functionality. A study of the mechanism showed that the activator (FeIIX2/L) and the additional initiator were generated by the photochemical reduction of FeIIIX3/L in the presence of a monomer. This work provides an environmentally benign ATRP to synthesize well-defined water-soluble materials.

1,2,4-Triazolium perfluorobutanesulfonate (1), a novel, pure protic organic ionic plastic crystal (POIPC) with a wide plastic crystalline phase, has been explored as a proof-of-principle anhydrous proton conductor for all-solid-state high temperature hydrogen/air fuel cells. Its physicochemical properties, including thermal, mechanical, structural, morphological, crystallographic, spectral, and ion-conducting properties, as well as fuel cell performances, have been studied comprehensively in both fundamental and device-oriented aspects. With superior thermal stability, 1 exhibits crystal (phase III), plastic crystalline (phase II and I) and melt phases successively from −173 °C to 200 °C. Differential scanning calorimetry and temperature-dependent powder X-ray diffraction (XRD) measurements together with polarized optical microscopy and thermomechanical analysis reveal the two solid–solid phase transitions of 1 at 76.8 °C and 87.2 °C prior to the melting transition at 180.9 °C, showing a wide plastic phase (87–181 °C). Scanning electron microscopy displays the morphology of different phases, indicating the plasticity in phase I. Single-crystal XRD studies reveal the molecular structure of 1 and its three-dimensional N–H⋯O hydrogen bonding network. The influence of the three-dimensional hydrogen bonding network on the physicochemical properties of 1 has been highlighted. The temperature dependence of hydrogen bonding is investigated by variable-temperature infrared spectroscopy. The sudden weakening of hydrogen bonds at 82 °C seems to be coupled with the onset of orientational or rotational disorder of the ions. The temperature dependence of ionic conductivity in the solid and molten states is measured via impedance spectroscopy and current interruption technique, respectively. The Arrhenius plot of the ionic conductivity assumes a lower plateau region (phase I, 100–155 °C) with a low activation energy of ∼36.7 kJ mol−1 (i.e. ∼0.38 eV), suggesting likely a Grotthuss mechanism for the proton conduction. Variable-temperature infrared analysis, optical morphological observations, and powder XRD patterns further illustrate the structural changes. Electrochemical hydrogen pumping tests confirm the protonic nature of the ionic conduction observed in the lower plateau region. Finally, measurements of the open circuit voltages (OCVs) and the polarization curves of a dry hydrogen/air fuel cell prove the long-range proton conduction. At 150 °C, a high OCV of 1.05 V is achieved, approaching the theoretical maximum (1.11 V).

The origin of the low-energy emission of fluorene-based rod-coil block copolymers still remains controversial. In this work, a series of polyfluorene-based rod-coil block copolymers having different coil segments, i.e., poly[2,7-(9,9-dihexylfluorene)]-block-poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate, (PF-b-PHFBMA), PF-b-poly(butylmethacrylate) (PF-b-PBMA), PF-b-poly(2-hydroxyethyl methacrylate) (PF-b-PHEMA) and PF-b-poly(acrylic acid) (PF-b-PAA), were synthesized using the ATRP technique. The optical and surface properties and thermal behaviors of these copolymers were systematically investigated. In particular, different thermal treatment conditions, including annealing temperature, annealing time and annealing atmosphere were introduced to study the effect of coil segment on the copolymer spectral stability. The incorporation of PBMA, PHEMA and PAA segments to PF could indeed improve the copolymer spectral stability, while the PHFBMA block brought undesirable low-energy emission. In addition, water contact angle (WCA) measurements of the copolymer films before and after annealing further demonstrated that the low-energy emission of PF-based rod-coil block copolymers was attributed to the molecular aggregation rather than the formation of fluorenone defects.

5-Hydroxymethylfurfural (5-HMF) which can be produced from cellulose is considered as one of the promising green platform chemicals. In this work, the conversion of cellulose to 5-HMF was carried out through hydrolysis in a batch reactor using the SO42−/Ti-MCM-41 catalyst at a temperature of 463–503 K. Two analytical techniques including the 3,5-dinitrosalicylic acid (DNS) method and high performance liquid chromatography (HPLC) were employed to track the time evolution of the main reagents, i.e., cellulose, 5-HMF and reducing sugar. Based on the typical kinetic experiments for the cellulose hydrolysis, a comprehensive hydrolysis mechanism was introduced to describe the heterogeneous hydrolysis of cellulose to 5-HMF. A corresponding kinetic model was proposed on the basis of the hydrolysis mechanism and the mass balance law. The results show that the predicted data obtained via the suggested model agree well with the experimental results. In addition, some data from the open reports were referred for further model verification in this work. The kinetic model suggested in this work is a mechanism model for the heterogeneous catalytic cellulose hydrolysis process, which is different from the previous first-order kinetic model.

A series of fluorene-based rod–coil block copolymers with different lengths of fluorine-containing coil segments (poly[2,7-(9,9-dihexylfluorene)]-block-poly (2,2,3,3,4,4,4-heptafluorobutyl methacrylate), PF-b-PHFBMA) were well designed and successfully synthesized via atom transfer radical polymerization (ATRP). The thermal behavior, optical properties and surface properties of these rod–coil block copolymers were investigated. The thermal properties of the copolymers presented a good thermal stability, while the optical properties did not show a noticeable dependence on the lengths of the coil segments. In addition, they showed a high dependence on the self-assembly behavior in selective solvents. The surface properties were obviously influenced by the structure of the micelles formed in different selective solvents (i.e. THF, CHCl3 and C2F3Cl3). The incorporation of the fluorine-containing coil segments in the polyfluorene-based polymers yielded a low energy surface and various interesting surface morphologies, which gives the polymers many potential applications.

A series of brush copolymers (i.e. poly(methyl methacrylate (MMA)-co-2-(2-bromoisobutyryloxy)ethyl methacrylate (BIEM)-graft-acrylic acid (AA))) having three backbone composition profiles, i.e. random, gradient and block, were synthesized via the combination of atom transfer radical polymerization (ATRP)/model-based semibatch ATRcoP and the “grafting from” method. These samples allowed us to systematically investigate the effects of the composition profile (including the grafting density corresponding to the composition profile) on the micelle formation and pH responsivity of the brush copolymers in solution. FTIR, 1H NMR and GPC were used to provide evidence for the formation of the well-defined brush copolymers. TEM, light transmittance and DLS were used to investigate the self-assembly and pH responsivity of the resulting copolymers. It was found that the micelles formed by these copolymers underwent a different conformational transition caused by the change from acidic to basic in the solution. These transitions were mainly influenced by pH and composition profile since the composition profile also had a strong effect on the acid-dissociation degree of the brush copolymer.