scholarly journals Polymeric Matrices for Lasing Dyes: Recent Developments

1998 ◽  
Vol 18 (1-2) ◽  
pp. 63-84 ◽  
Author(s):  
A. Costela ◽  
I. Garcia-Moreno ◽  
J. M. Figuera ◽  
F. Amat-Guerri ◽  
R. Sastre

An overview of recent results obtained by our group on the development of polymeric solid-state media incorporating either Rhodamine or Coumarin dyes is presented. The effect on the laser performance of the rigidity and viscoelastic properties of the polymeric matrix has been investigated. Lasing efficiencies similar to those found in ethanolic solution, and improved photochemical stability, as compared with that obtained in previous polymeric materials, were demonstrated for solid solutions of Rhodamine 6G (Rh6G) in appropriate copolymer formulations of 2-hydroxyethyl methacrylate (HEMA) and methyl methacrylate (MMA). Further improvements in photostability were obtained when modified Rh6G molecules were copolymerized with HEMA and MMA. When samples of this new highly homogeneous gain medium were placed in a rotating system, where the laser medium was scanned in a continuous way, a stable laser output with no sign of degradation after 500,000 shots was accomplished for transversal pumping at 337 nm with 1.7 mJ pulses from a N2-laser at 2 Hz repetition rate. The effect on laser operation of different polymerization methods, dye concentration, and composition of the polymeric matrix was also investigated for Coumarin-doped gain media. Conditions were found that significantly improved both lasing efficiency and photostability in Coumarin 540A (C540A)-doped polymeric matrices. Insight into the main photodegradation mechanisms of this dye was provided by the study of fluorescence and lasing properties of a number of C540A solutions with increased viscosity, from liquid solution to solid polymer matrix.

2021 ◽  
Vol 11 (9) ◽  
pp. 4242
Author(s):  
Manggar Arum Aristri ◽  
Muhammad Adly Rahandi Lubis ◽  
Sumit Manohar Yadav ◽  
Petar Antov ◽  
Antonios N. Papadopoulos ◽  
...  

This review article aims to summarize the potential of using renewable natural resources, such as lignin and tannin, in the preparation of NIPUs for wood adhesives. Polyurethanes (PUs) are extremely versatile polymeric materials, which have been widely used in numerous applications, e.g., packaging, footwear, construction, the automotive industry, the lighting industry, insulation panels, bedding, furniture, metallurgy, sealants, coatings, foams, and wood adhesives. The isocyanate-based PUs exhibit strong adhesion properties, excellent flexibility, and durability, but they lack renewability. Therefore, this study focused on the development of non-isocyanate polyurethane lignin and tannin resins for wood adhesives. PUs are commercially synthesized using polyols and polyisocyanates. Isocyanates are toxic, costly, and not renewable; thus, a search of suitable alternatives in the synthesis of polyurethane resins is needed. The reaction with diamine compounds could result in NIPUs based on lignin and tannin. The research on bio-based components for PU synthesis confirmed that they have good characteristics as an alternative for the petroleum-based adhesives. The advantages of improved strength, low curing temperatures, shorter pressing times, and isocyanate-free properties were demonstrated by lignin- and tannin-based NIPUs. The elimination of isocyanate, associated with environmental and human health hazards, NIPU synthesis, and its properties and applications, including wood adhesives, are reported comprehensively in this paper. The future perspectives of NIPUs’ production and application were also outlined.


2003 ◽  
Vol 5 (21) ◽  
pp. 4745-4763 ◽  
Author(s):  
A. Costela ◽  
I. García-Moreno ◽  
R. Sastre

2000 ◽  
Vol 78 (3) ◽  
pp. 231-241 ◽  
Author(s):  
M D'Iorio

Molecular organic materials have had an illustrious past but the ability to deposit these as homogeneous thin films has rejuvenated the field and led to organic light-emitting diodes (OLEDs) and the development of an increasing number of high-performance polymers for nonlinear and electronic applications. Whereas the use of organic materials in micro-electronics was restricted to photoresists for patterning purposes, polymeric materials are coming of age as metallic interconnects, flexible substrates, insulators, and semiconductors in all-plastic electronics. The focus of this topical review will be on organic light-emitting devices with a discussion of the most recent developments in electronic devices.PACS Nos.: 85.60Jb, 78.60Fi, 78.55Kz, 78.66Qn, 73.61Ph, 72.80Le


2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Maria Rosa Antognazza ◽  
Ilaria Abdel Aziz ◽  
Francesco Lodola

Reactive Oxygen Species (ROS) play an essential dual role in living systems. Healthy levels of ROS modulate several signaling pathways, but at the same time, when they exceed normal physiological amounts, they work in the opposite direction, playing pivotal functions in the pathophysiology of multiple severe medical conditions (i.e., cancer, diabetes, neurodegenerative and cardiovascular diseases, and aging). Therefore, the research for methods to detect their levels via light-sensitive fluorescent probes has been extensively studied over the years. However, this is not the only link between light and ROS. In fact, the modulation of ROS mediated by light has been exploited already for a long time. In this review, we report the state of the art, as well as recent developments, in the field of photostimulation of oxidative stress, from photobiomodulation (PBM) mediated by naturally expressed light-sensitive proteins to the most recent optogenetic approaches, and finally, we describe the main methods of exogenous stimulation, in particular highlighting the new insights based on optically driven ROS modulation mediated by polymeric materials.


2015 ◽  
Vol 81 ◽  
pp. 877-890 ◽  
Author(s):  
Kashif Mahmood ◽  
Khalid Mahmood Zia ◽  
Mohammad Zuber ◽  
Mahwish Salman ◽  
Muhammad Naveed Anjum

2014 ◽  
Vol 16 (22) ◽  
pp. 10388-10397 ◽  
Author(s):  
Takeshi Ueki ◽  
Ryo Yoshida

Herein, we summarise the recent developments in self-oscillating polymeric materials based on the concepts of supramolecular chemistry, where aggregates of molecular building blocks with non-covalent bonds evolve the temporal or spatiotemporal structure.


Author(s):  
F Arán-Ais ◽  
C Ruzafa-Silvestre ◽  
MP Carbonell-Blasco ◽  
MA Pérez-Limiñana ◽  
E Orgilés-Calpena

The key to sustainable development in the footwear industry through the principles of circular economy lies in taking care of the design, as well as the introduction of innovative and more resource efficient materials and processes to reduce or avoid the use of water, energy, hazardous chemicals and to minimise emissions and waste. In fact, the environmental footprint is already being considered as another requirement of the footwear through eco-design. In this sense, previous studies carried out by INESCOP regarding its environmental impact in terms of carbon footprint showed that 15% of it corresponds to the assembly processes, mainly by adhesive joints, due to their content on organic solvents, hazardous chemicals and polymers from fossil origin. Therefore, this paper focuses on recent developments carried out by INESCOP on more sustainable adhesives and adhesion processes for the upper-to-sole assembly in the footwear manufacturing process, through different approaches. Firstly, bio-based reactive polyurethane hot melt adhesives have been synthesised using polyols from different renewable sources. Secondly, the use of the low-pressure plasma surface treatment to improve the adhesion of polymeric materials used as soling materials was assessed in order to reduce volatile organic compounds emissions, as well as the use of hazardous chemicals for total automation of the bonding process.


2019 ◽  
Vol 9 (3) ◽  
pp. 3926-3933 ◽  

Although, there have been numerous efforts in synthesis of polymers, their mechanical properties have limited their applications. Graphene has been investigated for excellent properties such as superior mechanical properties, high thermal conductivity that has attracted the attention of scientific community to employ graphene as a filler material in polymeric matrices to form composites with multi-functional capabilities. The excellent properties possessed by Graphene has motivated users to fabricate flexible nanocomposites that can be used for applications requiring superior mechanical, chemical and thermal performances. Characteristics of both the components if explored synergistically through proper structural and interfacial organization. The investigation in this direction has resulted into combination of graphene with variety of polymeric materials and hence the development of different graphene-based nanocomposites. The present work reviews the application of graphene-based nanocomposites in the biomedical domain. With this objective, the polymeric matrices suitable for biomedical applications as well as the techniques of producing graphene polymeric nanocomposites have been discussed. Finally the application particularly in biosensing, wound healing and drug delivery system has been discussed.


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