A range of polymerisable photochromic naphthopyrans were prepared via the synthesis of an acrylate moiety on either the naphthalene ring (R) and/or the di-aryl (Ar) rings on the 3-position of the naphthopyran. The monomers obtained (NA) were copolymerised with methyl methacrylate (MMA) and methyl acrylate (MA) by the RAFT (reversible addition fragmentation chain transfer) process in order to control the structure of the polymeric chains and accurately control the number of photochromic molecules per chain. Films were prepared with the synthesized photochromic polymers and their photochromic properties were assessed. We found that the fading rate of the photochromic dye was slower in a matrix of PMMA (higher T g ) than in a matrix of PMA (lower T g ). By producing block copolymers of PMMA-b-poly(MA-co-NA), the fading rate was increased, and the production of PS-b-poly(MA-co-NA) further enhanced the speed of switching, as phase separation occurred between the poly(MA-co-NA) block and the PS block. This study presents an example of tuning the photochromic properties of a dye via variation of the architecture of its polymeric support.

The microphase separation of diblock copolymers synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization, containing one monodisperse block (poly(methyl methacrylate), PMMA) and one polydisperse block (poly(butyl acrylate), PBA), was investigated in thin films (<100 nm). The formation of ordered microphase-separated domains was observed by atomic force microscopy (AFM) and resulted in four morphologies, depending on composition and film thickness: parallel lamellae, hexagonally packed perforated lamellae (PL), parallel cylinders (C | ), and hexagonally packed spheres, and in C | -to-PL-to-C | transitions. Polydispersity of the PBA block shifts the phase boundaries toward higher PBA volume fraction values with respect to those expected for monodisperse block copolymers and stabilizes the perforated lamella morphology. Neutron reflectivity data confirmed that lamellae parallel to the substrate form at a very low PBA volume fraction, f PBA ) 0.23. Polydispersity of the PBA block also has the effect of stabilizing each microphase domain over a film thickness regime larger than expected for monodisperse blocks. For the first time RAFT-polymerized block copolymers are shown to microphase separate with high reproducibility and with excellent degree of order, hence proving to be ideal systems to test the effect of polydispersity on microphase separation.

Toward the development of a practical and green approach for removing phosphate from water, a monolithic cryogel based on starch and calcium silicate hydrate (Cry–CSH) was employed as a phosphate adsorbent in a continuous flow system for the first time. The influence of flow rate, initial phosphate concentration, and adsorbent height on the adsorption efficiency was investigated. As the rate of flow and the initial concentration of phosphate increased, the total quantity of adsorbed phosphate dropped; however, the performance of the column was greatly enhanced by an increase in adsorbent height. The experimental data fit the Adams–Bohart model better than the Thomas and Yoon–Nelson models at the beginning of the adsorption process. To evaluate its applicability, the continuous flow system based on the monolithic Cry–CSH column was applied for the removal of phosphate from the discharge effluent of the Patong Municipality Wastewater Treatment Plant (Phuket, Thailand), achieving an excellent total adsorption of 94.61%.

Photochromic nanopatterns were produced from the self-assembly of poly(methyl methacrylate)-bpoly(n-butylacrylate) (PMMA-b-PBA) block copolymers incorporating a naphthopyran photochromic dye. The PMMA-b-PBA block copolymers were synthesized by reversible addition fragmentation chain transfer polymerization with a photochromic dye (9-acryloyloxy-[3,3-bis(4-methoxyphenyl)]-3Hnaphtho[2,1-b]pyran) attached to the PBA block (PMMA-b-P(BA-co-NA)). The very low glass transition temperature of the poly(n-butyl acrylate) (PBA) block allows for rapid decolouration of the naphthopyran dye, whilst the PMMA matrix permits the macroscopic rigidity of the photochromic film to be maintained. The resulting films exhibit the fastest rate of colour switching reported to date for a naphthopyran polymeric film. Furthermore, the PMMA-b-PBA block copolymer exhibits microphase separation in nanodomains of controlled and regular morphology, thus allowing the confinement of the photochromic dye in well-controlled nanostructures. This feature allowed us to design polymeric films exhibiting precisely defined photochromic nanopatterns.