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Urban inhabitants spend upwards of 90% of their time indoors where building design and mechanical air-handling systems negatively impact air quality, microbiome diversity and health outcomes. Urban bioremediation infrastructure designed to improve indoor environmental quality by drawing air through photosynthesizing plants and metabolically diverse rhizospheres have been investigated since the 1960s; however, in-depth analysis of the potential impacts on indoor environments is required: (1) although recent evidence has illustrated human microbiome alteration and associated health benefits related to exposure to green wall systems, the mechanism(s) of diversification have not yet been established, (2) microbial metabolism and airborne chemical dynamics are extraordinarily complex and hypotheses pertaining to rhizosphere microorganisms metabolizing pollutants require more attention. To explore these areas, we applied a shotgun metagenomic approach to quantify microbial diversity and establish preliminary metabolic profiles within active green wall modules spanning a range of growth media and plant selections. Results indicate that fundamental design decisions, including hydroponic vs. organic growth media, support rhizosphere microbiomes with distinct diversity and metabolic profiles which could impact system performance. The described relationships indicate fundamental green infrastructure design represents an opportunity to “grow” indoor microbial diversity and metabolisms with potential benefits for human pollutant exposure and health outcomes.
For more than 80 years, the scientific community has extensively used International Centre for Diffraction Data's (ICDD®) Powder Diffraction File (PDF®) for material characterization, including powder X-ray diffraction analysis. Historically, PDF was made available for two major material types: one for inorganic analysis and the other for organic analysis. In the early years of the PDF, this two-material approach was implemented due to limited computer capabilities. With Release 2024, ICDD provides a comprehensive database consisting of the entire PDF in one database called PDF-5+, comprised of more than one million entries (1,061,898). The PDF-5+ with a relational database (RDB) construct houses extensive chemical, physical, bibliographic, and crystallographic data, including atomic coordinates and raw data, enabling qualitative and quantitative phase analysis. This wealth of information in one database is advantageous for phase identification, materials characterization, and several data mining applications in materials science. A database of this size needs rigorous data curation and structural and chemical classifications to optimize pattern search/match and characterization methods. Each entry in the PDF has an editorially assigned quality mark. An editorial comment will describe the reason if an entry does not meet the top-quality mark. The editorial processes of ICDD's quality management system are unique in that they are ISO 9001:2015 certified. Among several classifications implemented in PDF-5+, subfiles (such as Bioactive, Pharmaceuticals, Minerals, etc.) directly impact the search/match in minimizing false positives. Scientists with specific field expertise continuously review these subfiles to maintain their quality. This paper describes the features of PDF with an emphasis on the newly released PDF-5+.
This paper describes novel computational design, simulation and fabrication techniques employed in the production of a large sound-absorbing sculpture called Phoenix, made entirely from mycelium-composite materials (myco-materials). Myco-materials are composites made of lignocellulosic agricultural waste fibers bound by fungal mycelium and are produced at commercial scale as alternatives for plastics, insulation foam, or styrene. Mycelium composite materials have known acoustical properties that can be tuned according to variables such as growing time, substrate type, substrate size and density. The fabrication method for producing the Phoenix sculpture revisits how we build performative and formal complexity in the most economic and sustainable way. The results indicate the potential for grown materials to be used in retrofit projects, allowing rooms to be customized in various acoustical situations, such as music or speech.
Environmental concerns surrounding textile production have increased the need and interest in developing material innovations and interdisciplinary approaches to offset this ecological impact. Bacterial cellulose is present in several industries, and its biologically produced form has shown potential use within fashion. Within the emerging field of biodesign, research surrounding bacterial cellulose textiles generally focuses on the initial sheeted growth, while alternative outputs and working methods remain scarce. Here, fibre reassembly is analysed by fully integrating broken down BC fibres with knitted structures. Material selection and working methods take a practice-led approach to experiment formulation in order to observe material behaviour as central to development. This project aims to create biocomposite textiles that enhance the properties of bacterial cellulose and expand its designable characteristics through low-tech working methods accessible from designerly backgrounds. The results are intended to inform further research in footwear design contexts, as basis to develop BC-based components. Experimentation shows BC fibres reassembled around the knitted structures, varying according to yarn choice and fermenting environment alteration. This demonstrates potential for material and methodology development while exploring co-design with living organisms. In the context of future applications, BC-based composite textiles can self-assemble at different growth stages, offering the possibility of material-driven approaches to spaces intersecting biology and design.
Emission from organic materials is usually fluorescence from decay of singlet states, but in LEDs a majority of the excited states generated are triplet states which can only decay by phosphorescence or by thermally-activated delayed fluorescence (TADF). To improve the potential maximum efficiency of LEDs, it is necessary to incorporate into the emissive material chromophores which are phosphorescent or which show TADF. The ways in which such units can be incorporated into polymers are described and compared and the device results to date and prospects for future development discussed.
This chapter discusses how to tune the orbital energy levels and bandgaps of copolymers containing arylene and/or heteroarylene units, so as to obtain materials for high efficiency LEDs, TFTs and OPVs. By careful selection of the structures, and optimisation of the molar masses, polymers have been made which show very high charge carrier mobilities due to efficient charge transport. Here control of the solid-state packing is important but high crystallinity does not seem to be necessary. Transistors can be made with mobilities superior to that of amorphous silicon, though their commercial viability remains unproven. Careful control of bandgaps, molar masses and solid-state order combined with the development of new acceptor molecules has led to the fabrication of OPV devices with efficiencies close to 20%, which is better than many commercial solar cells. The commercial viability of OPVs remains to be demonstrated with device lifetimes still needing improvement, but these results combined with the low cost of making and processing conjugated polymers suggests such devices could be competitive with current ones with further optimisation.
Intermediate between PPPs and LPPPs in structure are stepladder polymers in which the monomers contain two or more phenylene units which are connected by one or two atom bridges. The simplest and most widely studied of these are poly(dialkylfluorene)s (PDAFs) whose monomers are biphenyl units linked by one carbon bridges. These were developed as blue-emitting materials, but their emission is unstable due to formation of emissive ketone defects by oxidation of monoalkylfluorene impurities. This problem can be overcome by replacing the alkyl groups with aryl groups or by making the monomers by routes which give only fully dialkylated compounds. The efficiency of the devices can be improved by incorporation of charge-transporting groups, while the emission colour is tunable by incorporation of emissive dye units. The emission from PDAFs is a violet-blue, but pure blue emission has been obtained by making polymers from monomers containing a larger number of linked phenylene rings. Also discussed are the synthesis and properties of other step-ladder polymers such as polycarbazoles which are analogous to PDAFs but contain nitrogen instead of carbon bridges.
Methods for making films of insoluble poly(para-phenylene) (PPP) are described and its potential as a blue-emitting polymer discussed. Efficient methods for making soluble PPP derivatives have been developed but these polymers suffer from undesirable changes in their emission due to twisting of the polymer backbones caused by steric interactions between the solubilising side-chains or by the formation of emissive aggregates in the solid state. To overcome this, ladder-type PPPs (LPPPs) made from precursor polymers have been made and their structure–property relationships and potential utility in devices are discussed. Stable blue emission from LPPPs has proven to be difficult to obtain due to the formation of emissive defects, while their wide bandgaps and unsuitable frontier orbital energies have made them of limited use in other devices.
Unlike standard conjugated polymers which may contain a range of conjugation lengths in their emissive chromophores, polymers can be made in which there are isolated chromophores of identical size and properties. This chapter describes the various types of such polymers that can be made, the routes to their synthesis and their device performances. Their advantages and disadvantages compared to standard polymers are discussed.
The methods for synthesising by precursor routes films of insoluble poly(phenylene vinylene) (PPV), the prototypical poly(arylene vinylene) (PAV) are described and compared and its properties discussed. Methods for preparing soluble substituted PPVs are described and their structure–property relationships discussed. By suitable choice of structure, PAVs with emission colours ranging from the blue to the near infra-red have been made and tested in light-emitting diodes. The choice of substituents has also been used to enhance the charge accepting and transporting properties of PAVs, thus improving their efficiency in devices. The efficiency of polymer-based LEDs is also affected by the presence of defects in the polymer structures and methods have been developed to minimise these, enabling commercially-viable LEDs to be made using PAVs. The potential use of PAVs in OTFTs and OPVs is also discussed.
The methods for synthesising polyacetylene are discussed and compared. As unsubstituted polymer is insoluble, precursor methods must be used to make films suitable for use in devices. While the fact that doped polyacetylene is conducting is of scientific interest, its instability and lack of luminescece has made it useless for practical applications. Substituted polyacetylenes can be made which are both soluble and luminescent, making them potentially useful in LEDs.The synthesis and properties of such polymers are discussed as well as their structure–property relationships and potential for use in devices.
Taking the Myx Sail displayed at the Danish Design Museum as a case study, this article investigates the room acoustics of an architectural installation made of Mycelium Textiles. Mycelium Textiles represent a novel typology of mycelium-based composites (MBC). The Myx Sail absorbers are grown on a composition of different layers of plant fibres combining woven jute textile with hemp mat and loose wood wool substrate enhancing the mechanical and acoustic properties of the composite. Two complementary acoustic tests were conducted to measure the absorbing properties of the mycelium material and its effects on the acoustics of the exhibition hall. The results show that the sail acts effectively as an acoustic absorber especially in higher range of frequencies, reducing the reverberation time and improving speech intelligibility. The effect of the sail on the overall room acoustics is especially effective, if the sound source is placed directly underneath the sail. The results of a complementary survey amongst visitors on their subjective perception of comfort and well-being however indicate that the degree to which a grown surface (and by extension, a grown building) is perceived positively or negatively depends on the relationship the individual has with Nature.
Polythiophenes are the most widely studied class of heteroarene-based polymers. The properties of poly(3-alkylthiophene)s have been shown to depend upon the degree of regioregularity in the polymer backbone. Routes have been developed to make almost completely regioregular polymers with nearly 100% head-to-tail couplings. These regioregular polymers show much better chain packing in the solid state and significantly better charge carrier mobilities, making them suitable for use in OTFTs. They show less promise as LED materials due to low emission efficiencies, but are promising as solar cell materials. A combination of regioregular poly(3-hexylthipophene) and a fullerene acceptor is the most widely studied donor–acceptor pair in OPVs, with device efficiencies of over 5% combined with a relatively inexpensive synthesis, making it potentially commercially viable.