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In this work, initiated chemical vapor deposition (iCVD) has been employed as a one-step liquid-free process combining polymerization and coating for the encapsulation of 3D non-planar substrates. Coatings have been applied using iCVD specifically to encapsulate microparticles of a highly water-soluble crop protection compound (CPC) for controlled release. Release behavior has been compared among different coatings synthesized using different iCVD processing conditions, including varying degrees of polymer hydrophobicity, continuous and pulsed deposition, and crosslinking. iCVD has been found to provide tunable synthesis of hydrophobic, crosslinked polymers with control over mass diffusivity, and coating thickness for enhancing barrier properties.

Transition metal mediated living radical polymerisation of butyl methacrylate has been demonstrated with a copper(I) halide N-alkyl-2-pyridylmethanimine ligands based catalyst. Optimum conditions were found to be with copper(I) chloride and N-octyl-2-pyridylmethanimine catalyst at 65 °C where conversions of 85% were achieved with polymers of Mn = 8900 g mol−1 (theoretical = 8400 g mol−1) and PDI = 1.23. Both non-ionic and ionic surfactants were employed which were also made by living radical polymerisation. The non-ionic surfactant was a block copolymer of PMMA from a polyethyleneglycol macroinitiator (total Mn = 7600 g mol−1, PDI = 1.20) and the ionic surfactant PDMEAMA–PMMA (total Mn = 8000 g mol−1, PDI = 1.21) with the PDMEAMA block quaternized with MeI (13.8%, 28.4%, 47.7% and 100%). A range of ligands were employed in the suspension polymerisation by varying the alkyl group on the ligand increasing the hydrophobicity (alkyl = propyl (PrMI), pentyl (PMI), octyl (OMI), dodecyl (DMI) and octadecyl (ODMI)). The more hydrophobic ligands were found to be more effective due to lower partitioning into the aqueous phase. Block copolymers of P(EMA)–P(BMA) and P(MMA)–P(BMA) were prepared by first preparing macroinitiators via living radical polymerisation (Mn = 1600 g mol−1 (PDI = 1.23) for P(EMA) and Mn = 1500 g mol−1 (PDI = 1.22) for P(MMA)) and using them for initiation of BMA in suspension polymerisation. Block copolymers had Mn between 12,800 and 13,700 g mol−1 with PDI between 1.33 and 1.54. Block copolymer growth showed excellent linear first order kinetics wrt monomer and demonstrated characteristics expected of a living radical polymerisation. Particle sizes were measured by SEM and DLS with good agreement (1.4–2.8 μm) and SEM showed spherical particles were formed.

The use of copper(I) Schiff base complex catalysed atom transfer polymerisation of methacrylates is described. The use of a range of functional and multi-functional initiators enables the synthesis of a range of functional and star polymers to be prepared under undemanding synthetic conditions. End capping with silyl enol ethers allows for ω-functional polymers. The combination of novel initiators, functional monomers and end capping allows an unprecedented array of macromolecular structures to be produced with limited need for protecting group chemistry.

Schiff bases of types 1, 2, and 3, easily prepared by the condensation of primary amines with pyridine-2-carboxaldehyde, glyoxal, or 2-acetylpyridine, respectively, are described as ligands for a copper(I) catalyst in the atom transfer polymerization of a range of methacrylates in toluene and xylene solution. Increasing the length of the alkyl group on ligands of type 1 increases the solubility of the catalyst in nonpolar solvents. The rate of polymerization increases on going from R = ethyl to propyl; however, on increasing the length of R further, we see no effect on the rate. The molecular weight distribution is narrow for all ligands where R = n-alkyl, and the number-average molecular weight (Mn) increases linearly with conversion. A decrease in rate and a loss of control are observed when branching is introduced in the α-position of the side chain. The polymerization is approximately first order in initiator, 0.90 ± 0.22, CuBr, 0.90 ± 0.13, and methyl methacrylate, 0.93 ± 0.01. Polymerization with Cu...

This paper demonstrates that atom transfer polymerization of methyl methacrylate mediated by CuBr/N-alkyl-2-pyridylmethanimine complexes in toluene proceeds effectively at temperatures as low as 15 °C, while maintaining control over molecular weights and yielding narrow polydispersity indexes. The reaction can even be performed at −15 °C with a number average molecular weight, Mn, of 6980 and a polydispersity, PDI, of 1.28 being achieved in 116 h; however, the molecular weight control is less effective. The polymerizations were performed at 90, 60, 40, and 15 °C with the first-order rate plots, molecular weight vs conversion plots, and final polydispersity indexes consistent with little or no terminationliving/controlled polymerization. Methyl hydroquinone (MeHQ) has been demonstrated to accelerate the polymerization by a factor of 3−4 at temperatures below 40 °C. An activation energy, Ea, for polymerization in the absence of phenol was determined to be 60.3 kJ·mol-1 and is significantly reduced to 44.9 k...

The synthesis and structural characterisation of related novel copper-(I) and -(II) diimine complexes have been described and their application as catalysts for atom transfer polymerisation is noted. The unexpected formation of a methoxy bridged copper(II) diimine complex [{(C10H14N2)CuBr(µ-OMe)}2(MeOH)] 3 from the reaction of a copper(I) diimine complex with phenol is described. Compounds 3 and [{(C10H20N2)CuBr(µ-OMe)}2] 4 appear to be examples of a rare class of alkoxy bridged CuII complexes, with very few similar examples being crystallographically characterised previously.

The use ofchiral catalysts in the living radical polymerisation of methyl methacrylate via atom transfer polymerisation (ATP) has been investigated in an effort to control the stereochemistry of the polymer backbone. Two enantiomerically pure chiral catalysts have been prepared and used in the ATP of methyl methacrylate: the structurally characterised complex, bis[N-(1-phenylethyl)-2-pyridylmethanimine]copper() tetrafluoroborate, [Cu(C14H14N2)2 ][BF4 ], and the reaction product of copper() bromide with N-(1-cyclohexylethyl)-2-pyridylmethanimine, [Cu(C14H20N2)2 ][Br]. Both catalysts were found to be suitable for the ATP of methyl methacrylate in conjunction with either ethyl 2-bromo-2-methylpropanoate in xylene at 90 °C or 4-methoxybenzenesulfonyl chloride in diphenyl ether at 90 °C. The system yields polymer of relatively narrow polydispersity; however, the use of these chiral catalysts did not significantly affect the stereochemistry of the polymer backbone. This may be due to the chiral centre being too distant from the propagating site to exert any influence over the monomer addition step, or that the reaction proceeds via a completely free-radical mechanism. This is, however, the first time a discrete, structurally characterised copper complex has been used as an effective ATP catalyst. The bond lengths of the complexed ligand indicate the oxidation state of the copper to be +1 in the complex.

The effect of different N -pentyl-2-pyridylmethanimine derivatives 2a – f upon the rate of copper(I) mediated atom transfer radical cyclisation (ATRC) of 5 and living atom transfer radical polymerisation (ATRP) of methylmethacrylate were investigated.

A statistical library of well-defined ionic and non-ionic amphiphilic block copolymers of P(MMA/HEMA)-b-PDMAEMA and PEG-b-P(MMA/HEMA) were synthesised via living radical polymerisation employing the macroinitiator technique. All the block copolymers show monomodal peaks and narrow weight distributions, indicating they were obtained in controlled manner. Those copolymers were further modified in order to prepare inisurfs and surfmers. This yielded a selection of active surfactants of desired molecular weight and low polydispersity. Soap-free miniemulsion polymerisations of butyl methacrylate were carried out using the obtained active surfactants to prepare core–shell microcapsules in which various concentrations of inert oil, hexadecane, as a model system were encapsulated. The influence of the block copolymer structure on the particle formation was studied. The core–shell nature of the particles could be confirmed using scanning electron microscopy. Up to 66% of hexadecane could be incorporated in PBMA microcapsules.

Highly efficient exchange between the halogen arising from the copper(I) halide and the alkyl halide originating from the initiator occurs during atom transfer polymerisation of methyl methacrylate mediated by copper(I) N-alkyl-2-pyridylmethanimine complexes.

Atom transfer radical polymerisation of methyl methacrylate mediated by copper(I) bromide, alkyl bromides and N-pentyl-2-pyridylmethanimine has been shown to be enhanced by the addition of substituted phenols, traditionally used as radical inhibitors.