High-performance luminescent solar concentrators based on poly(Cyclohexylmethacrylate) (PCHMA) films

In this study, we report on the use of poly(cyclohexylmethacrylate) (PCHMA) as an alternative to the commonly used poly(methylmethacrylate) (PMMA) for the design of efficient luminescent solar concentrators (LSCs). PCHMA was selected due to its less polar nature with respect to PMMA, a characteristic that was reported to be beneficial in promoting the fluorophore dispersibility in the matrix, thus maximizing the efficiency of LSCs also at high doping. In this sense, LSC thin films based on PCHMA and containing different contents of Lumogen F Red 305 (LR, 0.2–1.8 wt%) demonstrated optical efficiencies (ηopt) comprising between 9.5% and 10.0%, i.e., about 0.5–1% higher than those collected from the LR/PMMA systems. The higher LR/polymer interactions occurred using the PCHMA matrix maximized the solar harvesting characteristics of the fluorophore and limited the influence of the adverse dissipative phenomena on the fluorophore quantum efficiency. These effects were also reflected by varying the LSC film thickness and reaching maximum ηopt of about 11.5% in the case of PCHMA films of about 30 µm

Luminescent solar concentrators: boosted optical efficiency by polymer dielectric mirrors

We report on the optical efficiency enhancement of luminescent solar concentrators based on a push\u2013 pull fluorophore realized using high dielectric contrast polymer distributed Bragg reflectors as back mirrors. The Bragg stacks are obtained by alternating layers of cellulose acetate and thin films of a new stable and solution processable hydrated titania\u2013poly(vinyl alcohol) nanocomposite (HyTiPVA) with a refractive index greater than 1.9 over a broad spectral range. The results obtained with these systems are compared with enhancements provided by standard Bragg reflectors made of commercial polymers. We demonstrate that the application of the Bragg stacks with photonic band-gap tuned to the low energy side of the dye emission spectrum induces a 10% enhancement of optical efficiency. This enhancement is the result of a photon recycling mechanism and is retained even in a scaled-up device where the Bragg mirrors are used in a mosaic configuratio

Luminescent solar concentrators from waterborne polymer coatings

This study reports for the first time the use of waterborne polymers as host matrices for luminescent solar concentrators (LSCs). Notably, three types of waterborne polymer dispersions based either on acrylic acid esters and styrene (Polidisp® 7602), acrylic and methacrylic acid esters (Polidisp® 7788) or aliphatic polyester-based polyurethane (Tecfin P40) were selected as amorphous coatings over glass substrates. Water soluble Basic Yellow 40 (BY40) and Disperse Red 277 (DR277) were utilized as fluorophores and the derived thin polymer films (100 μm) were found homogeneous within the dye range of concentration investigated (0.3-2 wt. %). The optical efficiency determination (ηopt) evidenced LSCs performances close to those collected from benchmark polymethylmethacrylate (PMMA) thin films and Lumogen Red F350 (LR) with the same experimental setup. Noteworthy, maximum ηopt of 9.5 ± 0.2 were recorded for the Polidisp® 7602 matrix containing BY40, thus definitely supporting the waterborne polymer matrices for the development of high performance and cost-effective LSCs

Aggregation Induced Emission as a new Tool for Polymer Traceability

Two relevant examples are described here concerning polymer composite films containing dyes of different structure characterized by luminescent responsiveness to external stimuli. These systems provides evicence on how the optical smart response can be exploited for the development of smart and intelligent polymer devices for sensing and safety applications

Molecular rotors with aggregation-induced emission (Aie) as fluorescent probes for the control of polyurethane synthesis

In this work, the use of fluorescent molecular rotors such as 9-(2,2-dicyanovinyl)julolidine (DCVJ) and 2,3-bis(4-(phenyl(4-(1,2,2-triphenylvinyl) phenyl)amino)phenyl)fumaronitrile (TPET-PAFN) was proposed for the real-time monitoring of polyurethane (PU) formation in a solution of dimethylacetamide starting with 4,4′-methylenediphenyl diisocyanate (MDI) and different polyethy-lene glycols (PEG400 and PEG600) as diols. Notably, relative viscosity variations were compared with fluorescence changes, recorded as a function of the polymerization progress. The agreement between these two parameters suggested the innovative use of a low-cost fluorescence detection system based on a LED/photodiode assembly directly mountable on the reaction apparatus. The general validity of the proposed experiments enabled the monitoring of polyurethane polymerization and suggested its effective applications to a variety of industrial polymers, showing viscosity enhancement during polymerization

Front Cover: Macromol. Chem. Phys. 6/2014

The preparation of different styrene-based polymer films containing small amounts of tetraphenylethylene (TPE) and the evaluation of their photoluminescent behavior are reported. TPE molecular rotors show brilliant blue emission in a poor solvent or in a glassy styrene-based polymer matrix, where the intramolecular rotations of its aryls result as being completely arrested, but the fluorescence is weakened to pale green and eventually to a faint signal when good solvents or viscous but not glassy polymer matrices are used. This behavior suggests potential benefits in applications such as polymer traceability. Further details can be found in the article by G. Iasilli, A. Battisti, F. Tantussi, F. Fuso, M. Allegrini, G. Ruggeri, and A. Pucci on page 499

Make Mission Impossible Feasible: The Experience of a Multidisciplinary Team Providing Treatment for Alcohol Use Disorder to Homeless Individuals

Aim: People experiencing homelessness are often excluded from treatment programs for alcohol use disorder (AUD). The goal of this study was to describe the impact of a multidisciplinary treatment program on alcohol consumption and social reintegration in individuals with AUD experiencing homelessness.Methods: Thirty-one individuals with AUD experiencing homelessness were admitted to an inpatient unit for 5-6 days for clinical evaluation and to treat potential alcohol withdrawal syndrome. A group of volunteers, in collaboration with the Community of Sant'Egidio, provided social support aimed to reintegrate patients. After inpatient discharge, all patients were followed as outpatients. Alcohol intake (number drinks/day), craving and clinical evaluation were assessed at each outpatient visit. Biological markers of alcohol use were evaluated at enrollment (T0), at 6 months (T1) and 12 months (T2).Results: Compared with T0, patients at T1 showed a significant reduction in alcohol consumption [10 (3-24) vs 2 (0-10); P = 0.015] and in gamma-glutamyl-transpeptidase [187 (78-365) vs 98 (74-254); P = 0.0021]. The reduction in alcohol intake was more pronounced in patients with any housing condition [10 (3-20) vs 1 (0-8); P = 0.008]. Similarly, compared with T0, patients at T2 showed significant reduction in alcohol consumption [10 (3-24) vs 0 (0-15); P = 0.001], more pronounced in patients with any housing condition [10 (3-20) vs 0 (0-2); P = 0.006]. Moreover, at T2 patients showed a significant reduction in gamma-glutamyl-transpeptidase [187 (78-365) vs 97 (74-189); P = 0.002] and in mean cell volume [100.2 (95-103.6) vs 98.3 (95-102); P = 0.042].Conclusion: Patients experiencing homelessness may benefit from a multidisciplinary treatment program for AUD. Strategies able to facilitate and support their social reintegration and housing can improve treatment outcomes