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[EN] The macromolecular dynamics of dendronized copolymer membranes (PECHs), obtained by chemical modification of poly(epichlorohydrin) with the dendron 3,4,5-tris[4-(n-dodecan-1-yloxy)benzyloxy] benzoate, was investigated. In response to a thermal treatment during membrane preparation, these copolymers show an ability to change their shape, achieve orientation, and slightly crystallize, which was also observed by CP-MAS NMR, XRD, and DSC. The phenomenon was deeply analyzed by dielectric thermal analysis. The dielectric spectra show the influence of several factors such as the number of dendritic side groups, the orientation, their self-assembling dendrons, and the molecular mobility. The dielectric spectra present a sub-Tg dielectric relaxation, labelled as gamma, associated with the mobility of the benzyloxy substituent of the dendritic group. This mobility is not related to the percentage of these lateral chains but is somewhat hindered by the orientation of the dendritic groups. Unlike other less complex polymers, the crystallization was dismantled before the appearance of the glass transition (alpha(Tg)). Only after that, clearing transition (alpha(Clear)) can be observed. The PECHs were flexible and offered a high free volume, despite presenting a high degree of modifications. However, the molecular mobility is not independent in each phase and the self-assembling dendrons can be eventually fine-tuned according to the percentage of grafted groups., This research was funded by the Spanish Ministry of Science, Innovation and Universities, grant POLYDECARBOCELL (ENE2017-86711-C3-1-R, ENE2017-86711-C3-3-R).

Unoriented and oriented membranes based on dendronized polymers and copolymers obtained by chemical modification of poly[2-(aziridin-1-yl) ethanol] (PAZE) with the dendron 3,4,5-tris[4-(n-dodecan-1-yloxy)benzyloxy]benzoate were considered. DSC, XRD, CP-MAS NMR and DETA, contribute to characterize the tendency to crystallize, the molecular mobility of the benzyloxy substituent, the dendritic liquid crystalline group and the clearing transition. The orientation of the mesogenic chain somewhat hindered this molecular motion, especially in the full substituted PAZE. The fragility, free volume and thermal expansion coefficients of these membranes near the glass transition are related to the orientation and the addition of the dendritic groups. PAZE-based membranes combine both order and mobility on a supramolecular and macroscopic level, controlled by the dendritic group and the thermal orientation, and open the possibility of preparing membranes with proper channel mobility that promotes selective ionic transport.

Our investigation was focused on the preparation and characterization of novel plasters based on Carboxymethyl Chitosan derivative (CMC), to be used for the treatment of radiation dermatitis with Biologic Active Compounds (BACs) in a moist wound-healing environment. After performing the extraction and characterization of BACs from Cistus L., we optimized the BACs/CMC solution for subsequent plaster preparation. Then, plasters were prepared by dip-coating with a different number of layers, and we characterized them by Environmental Scanning Electron Microscopy (ESEM), Contact Angle (CA) and release tests in water for 24 h. Taking into account the flexibility of the plasters and the amount of released BACs after 24 h, the sample obtained after two dip-coating steps (2La) appeared promising in regard to comfortable mechanical properties and active principles administration. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test performed on keratinocytes cultured in standard medium shows that cells treated with released extract from 2La start to proliferate, extend cellular viability and form colonies typical for epidermal cells.

Our investigation was focused on the preparation and characterization of novel plasters based on Carboxymethyl Chitosan derivative (CMC), to be used for the treatment of radiation dermatitis with Biologic Active Compounds (BACs) in a moist wound-healing environment. After performing the extraction and characterization of BACs from Cistus L., we optimized the BACs/CMC solution for subsequent plaster preparation. Then, plasters were prepared by dip-coating with a different number of layers, and we characterized them by Environmental Scanning Electron Microscopy (ESEM), Contact Angle (CA) and release tests in water for 24 h. Taking into account the flexibility of the plasters and the amount of released BACs after 24 h, the sample obtained after two dip-coating steps (2La) appeared promising in regard to comfortable mechanical properties and active principles administration. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test performed on keratinocytes cultured in standard medium shows that cells treated with released extract from 2La start to proliferate, extend cellular viability and form colonies typical for epidermal cells.

Cancer is a major health issue concerning to all of us. Current treatment options are still limited due to not-selective action. Encapsulation is contemplated as an innovative approach to address systemic toxicity and tumor resistance caused by traditional therapies, while increasing encapsulated compounds bioavailability. The coating material of capsules strongly determines the success of the system. Since alginate has been proved non-toxic, biocompatible and biodegradable, it is considered a potential vehicle for therapeutic factors encapsulation. Besides, it has the particular ability to form hydrogels, which hold a high-water content and greatly resemble to natural soft tissues. The present review exposes the state-of-the-art and the most sophisticated alginate-based systems for cancer therapy and research. It begins with an overview of alginate hydrogels and the qualities that make them especially suitable for biomedical applications. In the following section, the application of alginate hydrogels as pioneering strategies for cancer treatment is described. Several examples of alginate-based delivery systems of therapeutic drugs, proteins and nucleic acids are provided. Significant emphasis is placed in both oral delivery systems and colorectal cancer therapy. Moreover, the role of alginate 3-D scaffolds for both cell culture and delivery is explained. Lastly, other applications of alginate-based hydrogels such as tumor biomarkers immunosensing and fluorescent surgical marker are included.

A molecular design approach was used to create asymmetrical visible light-triggered azo-derivatives that can be good candidates for polymer functionalization. The specific electron&ndash, donor substituted molecules were characterized and studied by means of NMR analyses and UV-visible spectroscopy, comparing the results with Time Dependent Density Functional (TD-DFT) calculations. A slow rate of isomerization (ki = 1.5 &times, 10&minus, 4 s&minus, 1) was discovered for 4-((2-hydroxy-5methylphenyl) diazenyl)-3-methoxybenzoic acid (AZO1). By methylating this moiety, it was possible to unlock the isomerization mechanism for the second molecule, methyl 3-methoxy-4-((2-methoxy-5-methylphenyl) diazenyl)benzoate (AZO2), reaching promising isomerization rates with visible light irradiation in different solvents. It was discovered that this rate was heightened by one order of magnitude (ki = 3.1 &times, 3 s&minus, 1) for AZO2. A computational analysis using density functional (DFT/PBE0) and wavefunction (QD-NEVPT2) methodologies provided insight into the photodynamics of these systems. Both molecules require excitation to the second (S2) excited state situated in the visible region to initiate the isomerization. Two classic mechanisms were considered, namely rotation and inversion, with the former being energetically more favorable. These azo-derivatives show potential that paves the way for future applications as building blocks of functional polymers. Likewise, they could be really effective for the modification of existing commercial polymers, thus transferring their stimuli responsive properties to polymeric bulky structures, converting them into smart materials.

At present, Polylactic acid (PLA) is one of the most used biodegradable polyesters. The good properties and its biodegradability make that PLA can replace the fossil fuel derived polymers in different applications. PLA can be synthesized by using different methodologies. Among them, the most widely used forms on an industrial scale are the direct polycondensation of Lactic acid and the ring-opening polymerization of cyclic Lactide. The final properties of the obtained PLA are dependent on the used stereoisomers of the raw materials (Lactic acid and/or Lactide) and the conditions employed to polymerize them. Therefore, the comprehension of the synthetic mechanism of PLA is crucial to control the stereoregularity of PLA, which in turn results in an improvement of the polymer properties. So, distinct mechanisms for the synthesis of PLA by ring-opening polymerization using different catalysts systems (organometallic catalysts, cationic catalyst, organic catalyst, bifunctional catalysts) are examined in this review.

The growing interest of oncologists in natural compounds such as polyphenols and flavonoids is encouraging the development of innovative and efficient carriers for the delivery of those drugs. This study examines carboxymethyl chitosan-based microcapsules created by spray drying as a method for delivering biologically active compounds isolated from the Cistus herb. Effects of sterilization and encapsulation on the polyphenol and flavonoid content of Cistus extract were investigated to optimize the production process. Furthermore, in vitro studies were carried out to examine the anticancer properties of sterilized polyphenols and flavonoids on glioblastoma cells isolated from oncological patients. Acquired results show high anticancer potential towards glioblastoma as well as low cytotoxicity towards non-cancer cell lines by the substances in question. Steam sterilization is shown to affect the content of biologically active compounds the least. We demonstrate that the investigated form of drug encapsulation is both efficient and potentially possible to scale up from the viewpoint of the pharmaceutical industry.

Novel functional polymeric microcapsules, based on modified azobenzene moieties, are exhaustively investigated, both from a theoretical and experimental points of view. Theoretical calculations and several measurements demonstrate that visible light can act as a trigger for release of encapsulated material, as a consequence of trans-cis isomerization which modifies microcapsule surface topography and can induce a “squeezing” release mechanism. Interfacial polymerization of an oil-in-water emulsion is performed and leads to core-shell microcapsules which are characterized by means of atomic force microscopy (AFM), optical microscopy (OM), scanning electron microscopy (SEM) and light scattering. These analyses put into evidence that microcapsules’ size and surface morphology are strongly affected by irradiation under visible light: moreover, these changes can be reverted by sample exposure to temperatures around 50°C. This last evidence is also confirmed by NMR kinetic analyses on modified azobenzene moiety. Finally, it is shown that these smart microcapsules can be successfully used to get a controlled release of actives such as fragrancies, as a consequence of visible light irradiation, as confirmed by an olfactive panel.

Dendronized polyethers give rise to columnar LC structures which can successfully act as cation transport materials. Therefore, we prepared two different materials, based on Poly(epichlorohydrin-co-ethylene oxide) (PECH-co-EO) grafted with methyl 3,4,5-tris[4-(n-dodecan-1-yloxy)benzyloxy] benzoate, containing 20% or 40% modified units, respectively. The obtained polymers were characterized by differential scanning calorimetry (DSC), X-ray diffraction and optical microscopy between crossed polars (POM) and compared to the unmodified PECH-co-EO. In order to reach efficient transport properties, homeotropically oriented membranes were prepared by a fine-tuned thermal annealing treatment and were subsequently investigated by dynamic mechanical thermal analysis (DMTA) and dielectric thermal analysis (DETA). We found that the presence of the dendrons induces a main chain partial crystallization of the polyether chain and coherently increases the polymer Tg. This effect is more evident in the oriented membranes. As for copolymer orientation upon annealing, the cooling rate and the annealing temperature were the most crucial factors. DMTA and DETA confirmed that grafting with the dendron strongly hinders copolymer motions, but did not show great differences between unoriented and oriented membranes, regardless of the amount of dendrons.

We examine the behaviour of acrylic resin-based membranes containing natural anti-oxidants, such as Galla Chinensis tea powder extract (TP) and Taiwanese green propolis (TGP), in different concentrations ranging between 5 and 20 wt %. Membrane morphology was investigated by means of Environmental Scanning Electron Microscopy (ESEM), while the UV-curing reaction was monitored by Fourier-Transform Infra-red (FTIR) spectroscopy. In most cases Thermogravimetric (TG), Differential Scanning Calorimetric (DSC) and Dynamo-mechanical Thermal (DMT) analyses showed that the desirable characteristics of the UV-cured acrylic resin are not substantially altered by the presence of the organic fillers. The release kinetics of polyphenols and flavonoids, determined in water for TP-containing membranes (ETx) and in ethanol/water mixture (7:3 v/v) for TGP-containing ones (EPx), was satisfactory, reaching a plateau after 24 h. Finally, preliminary antibacterial tests against S. Epidermidis were performed on the membranes with higher additive amount and gave positive results for ET-type, on the contrary, no inhibitory effect was observed for the tested EP-type membranes.

We investigated the possibility of improving the performance of polysulfone (PSf) membranes to be used in carbon dioxide capture devices by blending PSf with a commercial polyethylene imine, Lupasol G20, previously modified with benzoyl chloride (mG20). Additive amount ranged between 2 and 20 wt %. Membranes based on these blends were prepared by phase inversion precipitation and exhibited different morphologies with respect to neat PSf. Surface roughness, water contact angles, and water uptake increased with mG20 content. Mass transfer coefficient was also increased for both N2 and CO2; however, this effect was more evident for carbon dioxide. Carbon dioxide absorption performance of composite membranes was evaluated for potassium hydroxide solution in a flat sheet membrane contactor (FSMC) in cross flow module at different liquid flow rates. We found that, at the lowest flow rate, membranes exhibit a very similar behaviour to neat PSf; nevertheless, significant differences can be found at higher flow rates. In particular, the membranes with 2 and 5 wt % additive behave more efficiently than neat PSf. In contrast, 10 and 20 wt % additive content has an adverse effect on CO2 capture when compared with neat PSf. In the former case, a combination of additive chemical affinity to CO2 and membrane porosity can be claimed; in the latter case, the remarkably higher wettability and water uptake could determine membrane clogging and consequent loss of efficiency in the capture device.

DOI: 10.1016/j.polymer.2016.10.047 URL: http://www.sciencedirect.com/science/article/pii/S0032386116309661 Filiació URV: SI Inclòs a la memòria: SI Poly[2-(aziridin-1-yl)ethanol] (PAZE) is a suitable polyamine candidate which can be dendronised with 3,4,5-tris[4-(n-dodecan-1-yloxy)benzyloxy]benzoic acid (TAP) in order to obtain liquid crystalline columnar polyamines, as previously reported. However, the resulting copolymers evidenced a strong tendency to crystallise which leads to the detriment of columnar phase stability and the mechanical properties of the resulting polymeric membranes. In order to overcome this drawback, we successfully prepared LC columnar polyamines based on poly[2-(aziridin-1-yl)ethanol] modified with both TAP and benzoyl chloride at different extents. The presence of the dendron group induces self-assembling into a columnar structure, due to an exo-recognition of the side-chain dendrons, while the benzoyl group is expected to inhibit polymer crystallinity. All copolymers, except one, have lower melting points and exhibit higher clearing temperatures (Tc), when compared to the LC polyamines obtained by modification of PAZE with TAP only, reported in previous studies. In all cases they exhibited LC columnar mesophases after annealing, as inferred by DSC, XRD and POM. When casted as membranes, these columnar copolyamines can be homeotropically oriented under thermal treatment at optimal conditions, as was confirmed by X-ray diffraction studies at low 2θ angles. Additionally, SEM microscopy was used in order to evaluate the morphology of the prepared membranes.

Membranes with a high but remarkably humidity-independent proton conductivity were prepared. Side-chain liquid crystalline polyethers (SCLCPs), based on poly(epichlorohydrin) (PECH) and poly(epichlorohydrin-co-ethylene oxide) (P(ECH-co-EO)), dendronized with potassium 3,4,5-tris[4-(n-dodecan-1-yloxy)benzyloxy]benzoate were specially designed for this purpose. When cast as membranes, these tailored polymers self-assembled into columns, driven by exo-recognition. They thus mimic the highly specific supramolecular organization observed in nature and present the first biomimetic material for proton transport out of which stable, oriented and self-sustained membranes could be prepared. As revealed by combined X-ray diffraction, Atomic Force Microscopy and Transmission Electron Microscopy, polymeric column formation was obtained in the cast membranes following a thermally induced homeotropical orientation. Two unique and highly desired properties were found in the resulting membranes. While conventional proton conducting membranes exploit an “acidic group-based” transport mechanism, the current columns pillaring across the membranes formed ionic paths, giving rise to a remarkable size-dependent antiport transport mechanism. It resulted in conductivity values in the range of 10−2–10−3 S/cm, comparable to current state-of-the-art Nafion membranes, but, most importantly, with a complete independency from relative humidity. Reported membranes thus open excellent opportunities for further fine-tuning of their properties, wider exploitation of the exceptional transport mechanism, and final applications in fuel cells and related fields.

A new generation of hybrid biomimetic membranes, combining dendronised liquid-crystalline poly[2-(aziridin-1-yl)ethanol] with different modification degrees and anodized aluminum oxide as support, is reported here. The hybrid membranes are prepared by impregnation of the support with a 30% THF polymeric solution. The presence and homogeneous distribution of the polymeric material inside the membrane is confirmed by Raman spectroscopy and line microanalysis. The polymers show tendency to self-assemble into columns, arraying into columnar liquid-crystalline mesophase. Columns homeotropical-like orientation, as a result of a thermal treatment at optimal conditions, is confirmed by X-ray diffraction studies at low 2θ angles. Polymeric wires, being potential ion conductive pathways, resulting from assembling of polymeric columns are detected by SEM microscopy. Low absorption values for water and aqueous methanol solution are observed for hybrid systems, which suggest limited contribution of water in ion transport. Altogether, the new generation of hybrid membranes represents a promising class of biomimetic materials able to form oriented channels inside inorganic support.

A breakthrough feature of visible-light responsive polymer nanocapsules relies on the possibility of customizing the release of the cargo material via precise tuning of the triggering wavelength in the visible spectrum. Here, visible-light responsive polymer nanocapsules are successfully fabricated through interfacial miniemulsion polymerization, introducing a comonomer based on modified ortho-substituted azobenzene in the capsule shell. Thyme essential oil and a model drug molecule, Coumarin-6, are encapsulated as core materials. Continuous irradiation with sunlight or visible light at different wavelenghts gives rise to smooth release patterns whose kinetics is studied as a function of the wavelength and intensity of the light source. Interestingly, an on-off release behavior is achieved when the capsules are irradiated with white or green light. Considering that visible light is readily available and unharmful to human beings, these intelligent delivery platforms are potentially applicable in a wide range of applications requiring a more sustainable approach, such as crop protection, cosmetics and packaging.

The development of antimicrobial active packaging constitutes a powerful tool to reduce waste and increase quality standards of perishable goods. Among numerous available antimicrobial agents, essential oils stand out for their renowned efficiency, and their use is beneficial due to their sustainability compared to other oil-based antimicrobials. In this work, we report on the use of photo-responsive nanocapsules containing thyme essential oil as functional coatings for polyethylene and polylactic acid films to obtain antimicrobial active packaging. Polymer surface activation treatment enhanced compatibility with nanocapsules solution. The films were analyzed to assess the structural and functional properties of the coating, evaluate morphological changes due to their photo-responsive behavior, and monitor the light-induced release of volatile thyme oil. It was found that 24 h after a 15-min UV exposure of the coated films, the concentration of thyme oil in the headspace was eight times higher with respect to un-irradiated films, thus confirming the efficiency of the light-triggered release system. Therefore, the manufactured films are proposed as on-demand release devices for application in non-contact antimicrobial active packaging.

The conversion of low-energy light into high-energy light, also known as upconversion, can be exploited in medicine (i.e. phototherapy, bioimaging), pharmacology (i.e. development of new drugs), consumer goods (i.e. development of new materials for cosmetic active compounds delivery). In this frame, lanthanides-based nanoparticles are fascinating examples of how upconverting nanoparticles can be employed to improve release in photo-responsive capsules. One of the main problems related to the use of such platforms is that the photo-triggered release is based on a limited range of available photochromic moieties, mostly responsive to UV or visible light irradiation. The short penetration length associated to these wavelengths make these systems hardly applicable in internal medical applications. NIR light, capable to penetrate biological tissues, is converted by lanthanide-based nanoparticles that can convert it to UV-vis, photo-triggering the moieties incorporated in the capsule shells and introducing the release of encapsulated materials. In this work a wide variety of photo-triggered capsules enhanced by the lanthanide-doped upconverting nanoparticles are reviewed. Finally, the aim of this review is to open an international discussion on this hot topic and to delight this platform technology as a novel powerful medical treatment. (C) 2019 Published by Elsevier B.V.

Summary Photosensitive microcapsules that reversibly switch upon visible light irradiation are attractive targets for drug delivery, fragrance release and pesticide delivery. In this study we report the development of visible light triggered microcapsules and demonstrate the concept of protection and remote release of a model, non-toxic perfume oil. Polyamide microcapsule shells containing visible light-sensitive ortho-substituted azobenzene moieties in the main chain of the polymer were prepared by oil-in-water interfacial polymerization method. Microcapsules surface and cross-section morphologies were observed by SEM. Triggered perfume release during light irradiation was monitored by means of GC/MS. We suggest that the mechanism of perfume release from the microcapsules shell is based on decrease of modified azobenzene length during light illumination. This visible light-induced compression of microcapsules offers a new way to modulate the release of encapsulated materials.

This work reports on the preparation of UV-light responsive nanocapsules based on cross-linked polyamide, obtained by miniemulsion interfacial polymerization. The photo-triggered E-Z transition of azobenzene moieties of the polymer backbone enabled controlled release of encapsulated molecules. Appropriate selection of emulsion conditions allowed tailoring size distribution of the resulting nanocapsules. The light responsiveness of the nanocapsule systems has been evaluated by monitoring size change and release of a fluorescent probe upon UV irradiation, and an unambiguous relationship between capsule size and release kinetics has been highlighted. In particular, the smaller the capsule size, the faster the achieved release. Therefore, the photoresponsiveness of the nanosized capsule systems can be modulated by a proper selection of emulsion and processing parameters. The significance of the reported results lies in the size control of the encapsulating particles, which in turn enables to tailor their swelling kinetics, and to precisely design light-controlled release systems. (C) 2015 Elsevier Ltd. All rights reserved.

A family of self-assembling LC columnar polyethers were prepared by chemical modification of linear polyglycidol with a polymerization degree equal to 20, with the dendron 3,4,5-tris[4-(n-dodecan-1-yloxy)benzyloxy]benzoic acid by Steglich esterification. The modification degrees of the resulting LC polyethers ranged between 8 and 43%. All the obtained copolymers exhibited LC behavior and the higher the modification degree, the higher the clearing range, as expected. Mesophase self-assembling depended on the amount of dendrons introduced: in the case of modification degree ranging around 10%, the copolymers exhibited lamellar columnar structure, while for the highest modification degrees, hexagonal columnar mesophase resulted; in the case of intermediate degree of modification, the copolymers exhibited a rectangular columnar mesophase. Oriented membranes could be prepared from modified polyglycidol with different modification degrees and showed promising proton permeability values. Therefore, these materials are proposed as interesting candidates for proton transport materials.

Mixtures of methacrylic polymers are the most common materials for making composites to be used as resins for dental and cosmetic applications. Some of these mixtures are composed by poly(ethyl methacrylate) (PEMA) and poly(methyl methacrylate) (PMMA), which constitute a solid component to be mixed with a liquid component made out of methacrylate monomers. The reaction between the thermal initiator benzoyl peroxyde (BPO) present in the solid component and the activator of the polymerization process, N, N-dimethyl-p-toluidine (DMT) present in the liquid component, gives rise to thermoset materials. In the present study, different liquid formulations composed by a mixture of two methacrylic monomers, ethyl methacrylate (EMA) and triethylene glycol dimethacrylate (TEGDMA) for cosmetic applications, were prepared and characterized, using a commercial powder (POW) composed by PEMA and PMMA. With the aim of improving workability during final application of the material, it was necessary to slow down the polymerization rate of liquid formulations. Their thermal behavior was investigated by differential scanning calorimetric (DSC) in order to check the polymerization rate. Thermal stability of final materials was determined by thermogravimetric analysis (TGA). Dynamic mechanical thermal analysis (DMTA), microindentation hardness and impact tests were performed on final materials, to assess their performance with respect to standard formulation. The combination of thermal and mechanical properties allows choosing which formulations could be suitable for use in cosmetics.

Light‐triggered release of active ingredients from polymeric nanosized capsules can be employed in a wide range of applications, such as biomedicine, active packaging, and cosmetics. However, the preparation of core‐shell polymeric nanocarriers typically involves the use of toxic organic solvents. To improve the sustainability and safety of nanocapsule applications, we demonstrate that natural essential oils can be used both as a solvent and as an active material in light‐responsive nanocapsules synthesized via miniemulsion polycondensation. The documented antimicrobial, anti‐inflammatory, and antioxidant activity of essential oils enables the design of multipurpose light‐responsive delivery platforms. The photo‐responsive behavior of the capsules, achieved by means of photochromic azobenzene segments embedded in the capsule shell, is triggered by UV light irradiation (λmax = 360 nm). Light‐induced release kinetics of the essential oils and a fluorescent probe molecule, coumarin‐6, are evaluated via UV‐vis spectroscopy and spectrofluorimetry, respectively, demonstrating the efficiency and reliability of the release mechanism. Biological tests prove that the capsules are non‐cytotoxic and readily internalized by cells, indicating the suitability of these smart nanocarriers for biological applications

Liquid-crystalline elastomer (LCE) nanocomposites exhibiting shape memory properties were prepared by dispersing a chemically modified graphene oxide (GO) in a smectic, lightly crosslinked epoxy resin obtained by curing p-bis(2,3-epoxypropoxy)-α-methylstilbene (DOMS) with sebacic acid (SA). Chemical grafting of DOMS monomer on GO particle surface improved interfacial adhesion between the epoxy matrix and the filler. The obtained nanocomposite films were characterized in their phase behavior, morphological and thermal properties. Furthermore, their shape memory properties were analyzed through two-way thermomechanical cycling tests. The combination of the LCE liquid crystallinity and the efficient dispersion of functionalized GO resulted in toughened, highly oriented systems endowed with enhanced shape memory response. Incorporation of 0.15 wt.% GO resulted in a significant increase of spontaneous elongation and reduced actuation temperature during cycling thermomechanical tensile testing, demonstrating the potential of these systems as shape memory materials for sensors and actuators.

Controlled release of photosensitive systems is widely studied because of its numerous applications. However, just a few descriptions of the mechanism of this phenomenon have been reported. The aim of this study was to investigate the behaviour of a real system based on light-sensitive α-methylstilbene-based copolyester microcapsules with vanillin as an upload under UV irradiation. For this purpose we aimed to elucidate some of the structural features of the chains by means of quantum chemical calculations applying periodic boundary conditions. Additionally, the excitation energy of an approximated model was used to verify the influence of large size and various functionalities of attached groups on the system. From the optimized structure of trans and cis isomers, it was proved that trans-to-cis isomerization can be responsible for a main chain length reduction by 20% in comparison to the initial state, thus confirming the experimental findings. Moreover, the major influence of double bonds on photoactivity of the system was justified by comparison of the calculated UV-visible spectra of both forms with empirically obtained data which were in good agreement. © 2015 Society of Chemical Industry

Encapsulation offers broad scope of applications. It can be used to deliver almost everything from advanced drugs to unique consumer sensory experiences; it could be also employed as a protection system or a sensing material. This cutting-edge technology undergoes rapid growth in both academic and industrial conditions. Research in this matter is continuing to find a new application of microcapsules as well as to improve the methods of their fabrication. Therefore, in this review, we focus on the art of the encapsulation technology to provide the readers with a comprehensive and in-depth understanding of up-to-day development of microcapsule preparation methods. Our goal is to help identify the major encapsulation processes and by doing so maximize the potential value of ongoing research efforts.

Correction for ‘Functionalized fluorescent terephthalate monomers and their attempted polyester formation’ by Yvonne S. L. Choo et al., Org. Biomol. Chem., 2020, 18, 8735–8745, DOI: 10.1039/D0OB01533D.

The development of photo-responsive capsules to tune and control the sustained-release of encapsulated actives is a fascinating and challenging route to improve the performances and effectiveness of a wide range of delivery applications. In this work, we report the preparation of visible light-responsive capsules obtained via oil-in-water interfacial polycondensation between modified diacyl-chloride azobenzene moiety and diamine flexible spacer in the presence of cross-linkers with different structures and functionalities. The effect on the release profile of the encapsulated perfume oil was investigated using three flexible spacers with different lengths (1,8-diaminooctane, 1,6-diaminohexane and 1,4-diaminobutane) and two types of cross-linkers (1,3,5-benzenetricarbonyl trichloride and melamine). We analyzed how the properties of microcapsules can be tailored changing the design of the shell structure. Fine tuning of the perfume release profiles was obtained. The changes in capsules size and morphology due to visible light irradiation were monitored via light scattering, optical microscopy and atomic force microscopy. Perfume release was 50% faster in the systems prepared with melamine as the cross-linker. Modelling studies were carried out to support the discussion of the experimental results.