Poly(2-oxazoline)s (POxs) offer an unparalleled degree of functionalization in the fabrication of smart, functional polymers for a wide range of applications. By utilizing 2-ethyl-2-oxazoline and a unique hydrophobic 2-oxazoline monomer, 2-isostearyl-2-oxazoline, we report the synthesis of a library of functionalized poly(2-ethyl-2-oxazoline)s (PEtOxs) and poly(2-isostearyl-2-oxazoline)s (PiStOxs) that show incredible potential as dispersants of carbon black (CB) in water and dodecane. The initiation and termination of 2-oxazoline polymerizations by direct end-capping can be exploited to introduce a variety of end-groups. Herein, we utilize this methodology to report the efficient synthesis of anthracene-end-capped PEtOx and PiStOx. A small library of 9-(chloromethyl)anthracene-initiated polymers was also synthesized to increase the aromaticity to investigate its influence on the dispersion of CB. The solution behavior of the polymers in aqueous and nonaqueous media is studied via turbidity measurement, and their ability to disperse CB in water and dodecane systems is assessed by a UV-vis spectrophotometer. PEtOx and PiStOx both display characteristics of a good dispersant, and PiStOx exhibits better performance than a commercially available dispersant, presenting superior results than previously reported for POx.

Non-aqueous emulsions are employed for a host of important applications; however, their long-term stability often limits their use. 2D particles have been reported to provide greater emulsion stability compared to surfactants and isotropic particles as a result of their greater interfacial area interaction. Here, control over the particle size resulted in control over the droplet diameter and increased stability. Non-aqueous emulsions are widely employed; therefore, characterising the effect of the dimensions of 2D particles on their stability is key to making oil-in-oil (o/o) emulsions with enhanced properties. This study investigates the self-assembly of uniform 2D particles of a controlled size, and their application as Pickering particles in o/o emulsions. The correlation between 2D particle dimensions and emulsion characteristics was investigated, a comparison that has not been reported for o/o emulsions prior to this study.

By utilizing a unique hydrophobic 2-oxazoline monomer, we report the facile and efficient synthesis of a novel poly(2-ethyl-2-oxazoline)-block-poly(2-isostearyl-2-oxazoline) copolymer library via cationic ring-opening polymerization. Varying the hydrophilic-hydrophobic block ratios of the copolymers afforded good control over thermal properties such as the glass transition temperature, leading to an increase from 0 to 60 degrees C as the volume fraction of the 2-ethyl-2-oxazoline block increased. A solvent-free self-assembly method was employed to study the self-assembly behavior of the copolymer library. Thus, using thin film hydration, a wide range of self-assembled structures were obtained in aqueous solution. Structures such as micelles, short and long worms, and unilamellar and multilamellar vesicles were observed and characterized via dynamic light scattering and electron microscopy analysis. All structures exhibited excellent stability in solution at ambient temperatures over a 2 month period and showed thermoresponsive behavior.

Alkyl-functional polycaprolactones were prepared via direct and well-controlled ring-opening polymerisation and the relationship between the substituent position and polymerisation rate was investigated.

One-pot synthesis of dodecylthiol-endcapped oligo(2-ethyl-2-oxazoline)s via direct endcapping and thiol-yne click chemistry enables mono- and di-functionalized PEtOx amphiphiles to self-assemble into encapulating micelles.

Developing new friction modifiers with enhanced green credentials for the automotive industry is imperative to reduce man-made global warming. Recently, polymer-based particles have been of great interest for this application; however, control over their dimensions in different vectors has been limited. We report the crystallization-driven self-assembly (CDSA) of block copolymers in nonpolar and oil solvents, where both blocks contain an ester moiety in the backbone. Cylindrical micelles of controlled lengths were accessed via a living CDSA method, which, when transferred into a base oil, reduced the friction coefficient of the oil. Herein, we established a dimension-friction modification relationship using cylindrical polyester-based particles, which outperformed commonly used lubricants.

The diamino-bis(phenolate) chromium(III) complex, CrCl[L], 1 where [L] = dimethylaminoethylamino-N,N-bis(2-methylene-4,6-tert-butylphenolate) when pre-contacted with cocatalyst, bis(triphenylphosphine)iminium chloride, formed the bis(triphenylphosphine)iminium chromium(III) dichloride ate complex, 2. Complex 2 shows good activity for the ring-opening polymerization (ROP) of rac-lactide (rac-LA) and -caprolactone (-CL), ring-opening copolymerization (ROCOP) of cyclohexene oxide (CHO) and phthalic anhydride (PA), ROCOP of epoxides and CO2, and synthesis of terpolymers containing polylactide or polycaprolactone, polycarbonate, and polyester segments. For example, polyester-b-polycarbonates can be obtained through controlled ROCOP of PA and CHO giving, moderate molecular weight polymers with narrow dispersity (e.g. Mn = 8.7 kg mol-1 and Đ = Mw/Mn = 1.14), followed by addition of CO2 to generate polycarbonate chains and an increase in Mn to 17.6 kg mol-1 with Đ = 1.13.

In this paper a series of 7 salalen ligands based on an aminopyrrolidine backbone have been prepared and characterised. Several systems have been reduced to the salan ONNO type‐ligand. All ligands have been complexed to AlIII with Al(1–7)Me, Al(2a)(OiPr) and Al(7a)Me being characterised by single‐crystal X‐ray diffraction. In general the AlIII centres are best described as being in a trigonal bipyramidal geometry. The solution and solid‐state structures are discussed. All complexes have all been trialled for the production of PLA from rac‐lactide, the salalen complexes had a preference for heterotactic PLA (Pr = 0.71), whereas the salan had a more isotactic bias (Pm = 0.72). In all cases PLA with low dispersities and predictable molecular weights were prepared. The activity of the two classes of ligands is compared with the salan complexes appearing to be significantly more active than the salalen systems.

Controlling the microstructure of polymers through chemical reactivity is key to control the material properties of synthetic polymers. Herein we investigate the ring-opening copolymerization of a mixture of lactide and 2-ethyl-2-oxo-1,3,2-dioxaphospholane, promoted by an aluminum pyrrolidine monophenolate complex or 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). This monomer mixture provides fast access to amphiphilic copolymers. The reaction conditions control the copolymer microstructure, which has been determined via a combination of H-1 and P-31 NMR spectroscopy. The choice of initiator has a profound impact: both initiators produce tapered block copolymers but with reverse monomer selectivity. While the aluminum initiator favors the cyclic phosphonate monomer, DBU favors lactide polymerization. Moreover, a sequential control of temperature facilitates the preparation of block copolymers in one pot. Thermal properties measured by TGA and DSC correlate to copolymer architectures. This methodology is the first report of copolymerization between cyclic phosphonates and lactide and opens the possibility to tune the thermal properties, solubility, and degradation rates of the resulting materials.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

In this paper we report the full characterization (solution-state NMR spectroscopy and solid-state structures) of a series of Al(III) half-salan complexes and their exploitation for the ring-opening polymerization of rac-lactide. Depending on the ligand employed and stoichiometry of the complexation, structures of the form Al(X)(2)Me or Al(X)Me-2 were isolated. Interestingly Al(2)(2)Me and Al(2)Me-2 produce PLA with a strong isotactic bias (P-m up to 0.80), whereas all other complexes produced atactic PLA. This is in contrast to recent studies on similar salan ligand systems. PLAs with predictable molecular weights and narrow distributions were achieved. The results are discussed in terms of steric and electronic properties of the ligands.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Four dimeric lanthanide alkoxide complexes bearing ONNO bipyrrolidine salan ligands ((LH2)-H-Me/(LH2)-H-tBu) have been prepared with Nd, Sm and Yb. Depending on the metal and substituents, these complexes adopt varying coordination geometries. While investigating the hydrolytic degradation of these complexes, three dimeric mixed alkoxide/hydroxide and bis-hydroxide products were also prepared, isolated and characterised. Despite paramagnetism, H-1 NMR and diffusion ordered spectroscopy (DOSY) allowed additional characterisation alongside elemental and single-crystal X-ray diffraction analyses. These systems were very active for the controlled ring-opening polymerisation (ROP) of rac-lactide (LA), under industrially relevant melt conditions and in solution, yielding complete conversion within 5 minutes at [Ln] : [LA] ratios of up to 3000 : 1 in toluene, and at 80 degrees C, whilst retaining low dispersities (D = 1.1). H-1 DOSY NMR spectroscopy was employed to monitor polymer growth from the metal centres in situ, and revealed a dinuclear catalytically active species.

Herein the preparation and characterisation of a series of group 13 salan complexes, with a bipyrrolidine or N,N′-ethylenediamine backbone are disclosed. For the bipyrrolidine derived-salan ligand 1H2, the Al(III) and Ga(III) complexes are pseudo trigonal bipyramidal in the solid-state, whereas the In(III) complexes are best described as square based pyramidal structures. However, for the ethylenediamine derived-salan ligand 2H2, all complexes are effectively square based pyramidal in their structure. The complexes' solution behaviour is also investigated by NMR spectroscopic methods and it is observed that the solid-state structure is maintained in solution. The complexes have all been trialled for the ring opening polymerisation of rac-lactide. With In(1)Cl controlled polymerisation and narrow molecular weight distributions (1.01–1.08) are observed with heterotactic polylactide being prepared. Under the conditions tested the Ga(III) and Al(III) complexes were shown to be inactive.