Singapore

Absorbing the moisture from sweat evaporation would prevent the accumulation of sweat, and thus inhibit the growth of bacteria or fungi, providing a healthy and comfortable microclimate for people. However, there have been almost no such attempts. On the other hand, sweat has always been considered a waste resource and attempts to tap this free resource in the form of energy are relatively sparse. To realize these ideas, here we developed a cobalt-complex based super-hygroscopic material (Co-SHM). Integrating the Co-SHM into breathable and waterproof PTFE membranes, we designed new kinds of armpit pad, shoe lining, and insole, which can rapidly absorb the moisture from sweat evaporation to prevent sweat accumulation. The absorbed sweat can be transduced to energy through a Co-SHM based wearable energy harvesting device that consists of an eight-series-connection of electrochemical cells.

MATERIALS FOR HUMANITY (MH 21)

Super-Hygroscopic Film Based Wearables for Expediting Sweat Evaporation and Energy Harvesting

EMNLP 2021 is planned to be a hybrid event in Punta Cana, Dominican Republic, with both on-site and fully virtual participation possible. The experience for on-site participants would closely approximate a normal pre-COVID *ACL conference, with 5-6 thematically organized parallel sessions and live Q/A and interactive discussion immediately after the talks. Presentations by virtual participants will be equitably interleaved with those of on-site participants, projected on the auditorium screens as if on-site, and also followed immediately by live Q/A and interactive discussion at a time during reasonable waking hours for the virtual presenter. For all participants, on-site and virtual, who are unable to attend a session due to either time-zone issues or because they are participating in another session live, talk recordings and slides will be available online at a minimum after the live presentation (and in many cases before as well), and questions may be submitted in advance on session-specific discussion boards and answered live in session with the usual visual aids if desired.

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Please Note: The EMNLP registration system is not currently connected to the underline site as we are still in the process of building out EMNLP 2021. You will receive access instructions from underline the week of November 1st. 

Access is given only to EMNLP upon registration, if you have not registered please do so [here](https://2021.emnlp.org/registration).

Registered attendees will receive access the week of November 1st.

EMNLP 2021

EMNLP 2021 is planned to be a hybrid event in Punta Cana, Dominican Republic, with both on-site and fully virtual participation possible.

poster

**Please view our Welcome to MH21 video.**

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**Walkthrough Video**

Here is a Walkthrough showing how to navigate the conference and network with others 

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	 <font color="#5eb1bf"  size="6"><b>Organized by</font>
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	 <font color="#5eb1bf"  size="6"><b>In association with</font>
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	 <font color="#5eb1bf"  size="6"><b>Supported by</font>
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To access the MH 21 Conference, [please register](https://mh21.mrs.org.sg/event/da3f9651-429f-4763-81b2-ebd7311b6bc8/websitePage:206f7605-1731-41f9-8421-56d3890f398f)

MH 21 is arranged around 6 themes that focus attention on pressing needs that should be addressed to enhance the well-being of communities and provide a forum for presenting breakthrough discoveries.

Polylactic acid (PLA) mixed with long-persistent phosphor (Ca2BO3Cl: Eu2+, Dy3+) was prepared in this study. The sustainable yellow luminescence of the composites could be clearly observed. The mechanical properties of the composite filaments were tested, including maximal force and elasticity modulus. In particular, the influence of humidity on mechanical properties was studied and optimal mixing conditions were found. Finally, the prepared composite filaments were printed into a hollow dodecahedron and presented in this study.

PLA/Ca2BO3Cl: Eu2+, Dy3+, A Novel Sustainable Luminescence Composite Material for 3D Printing

Microporous structure plays a significant role in bone tissue engineering, to influence inductive bone formation and elevate bone ingrowth inside microporous scaffolds. We hereby fabricated microporous scaffolds by 3D printing with mixture of porogens and photopolymerizing resin. We tuned the microporosity of scaffolds from 0% to 36% by varying the porogen concentration in the inks from zero to 60 vol%. The microporosity and microspore size of scaffolds can affect in vitro expansion of preosteoblast cells. Our studies revealed that preosteoblast cells’ in vitro adhesion and proliferation were significantly mediated by the printed scaffolds. Cells proliferation on scaffolds with 20-30% microporosity showed much higher rate than on other scaffolds. In this microporosity range, scaffolds also showed much better cell spreading and morphologies. At a low level of microporosity (<7%), the cell proliferation rate was even lower than the solid scaffolds, which indicates that the microporous structure is “toxic” for cells at low microporosity range. A higher microporosity (> 35%) led to very poor cell attachment and is unfavorable for the proliferation of MC3T3-E1 cells. Furthermore, the printed dual macro-/micro-porous scaffolds showed higher proliferation rate of MC3T3-E1 cells as compared to mono-pore sized scaffolds, either the macro-porous or microporous structure.

3D printing fabricated bone scaffolds with macro and micro porous structures

Stabilizing Effect of the Polymer Matrix on Sputter-Anneal Fabricated Nanocomposite Thin Films

The flame retardancy for polymers is very demanding as a lot of polymers are flammable and decompose into small and volatile hydrocarbons upon pyrolysis. In the past, most effective flame retardants for polymers are halogen-based. With the increasing regulatory requirements on safety and environments, halogen-based flame retardants are gradually being replaced with non-halogenated flame retardants. Inorganic metal hydroxides, mainly aluminum hydroxide (ATH) and magnesium hydroxide (MDH), are the largest class of flame retardants by volume. Other non-halogenated flame retardants, such as phosphorus-, nitrogen- and silicon-based, show promises for this property. The up-to-date technique gaps are: (1) for inorganic flame retardants, high loading of 40 - 60 wt% is required, leading to worse mechanical properties and heavy weight, (2) for current non-halogenated ones, most of them are small molecules. Such small flame retardant molecules have relatively poor thermal stability and mechanical strength, and will slowly leach out from the composites surface, leading to performance deterioration and possible environmental pollution. The development of new flame retardants with higher efficacy, lower loading, higher strength and high stability are therefore in need. Targeting this, we have developed new flame retardants with polymeric nature, which theoretically possess the above advantages over the current ones, and demonstrated their effectiveness in various polymers like polypropylene, polyamide. The flame retardant long chains will entangle with polymer matrix chains, stabilizing the whole composites without leaching issues.

Polymeric Flame Retardants: a Promising Category for Enhanced Performance

Compatible polymer blends with synergetic performance play an integral part in modern society from household, automobiles to aerospace. Conventional miscible polymer systems often relies on strong chemical interactions, while the inherent entropy effects are often neglected. Using a combination of experiments and simulation, we show that entropy driving forces could control the phase structure and mechanical properties of polymer blends from commercial plastics, creating ultrahigh extensibility (~146%), while maintaining its transparency and high strength (~70MPa).

Entropy-driven Ultratough Biodegradable Polymer Blends

With the increasing demand for the high strength and high fracture toughness composites in aerospace, automobile and other structural applications, great efforts have been devoted to the development of carbon fiber reinforced thermoplastic composites. However, the majority of commercial carbon fibers are sized for reactive thermosetting epoxy matrix, and therefore cannot be used directly for thermoplastic resin impregnation due to the high processing temperatures and poor interfacial interactions with polymer matrix. In this work, novel surfactant-free aqueous dispersions were derived from commercial polyimide resins through emulsion/solvent evaporation technique. The obtained nano-dispersions with uniform particle size around 100 nm and a high Zeta potential of -48.1 mV were deposited on carbon fibers via electrochemical deposition and dip coating method, respectively. The sized carbon fibers were characterized by scanning electron microscopy (SEM) and thermogravimetric (TGA) analysis, and the sizing performance was assessed by single fiber pull-out testing using polyetherimide (PEI) as the polymer matrix. The results show that the prepared polyimide sizing presents a positive effect on the interfacial adhesion of carbon fiber/PEI composites. Moreover, the carbon fibers sized by electrochemical deposition method exhibit higher interfacial shear strength (IFSS) compared to the dip-coated ones due to the increased van der Waals forces between the PEI matrix and sizing layer as well as the chemical bonding between the sizing layer and carbon fiber surface. The developed aqueous polyimide nano-dispersions exhibit great potential for application in the manufacturing of continuous carbon fiber reinforced thermoplastic prepregs.



Novel polyimide-based aqueous nano-dispersions as sizing agents for carbon fiber-reinforced thermoplastic composites

PVA is a polymer containing a large number of hydroxyl groups, which can be used by microorganisms as a source of carbon and energy. Water-soluble PVA has three major advantages: good abrasion resistance, high oil resistance, and high viscosity. Narrow intermolecular gaps and strong intermolecular forces caused the PVA hydroxyl groups for etherification and acetalization reactions to form a flexible film. In this research, The polyvinyl alcohol (PVA) nanofibers with good water resistance and high orientation were prepared by electrospinning technology, and PVA fiber self reinforced PVA resin matrix composite membrane with high strength and high transmittance was successfully prepared by solution impregnation method and self reinforcing concept. The PVA composite film prepared in this paper has good light transmittance, and the light transmittance is more than 85% at the wavelength of 400-800 nm. Compared with pure PVA films, the strength and toughness of random PVA nanofiber reinforced composites (R-PVAF) (30 wt%) and oriented PVA nanofiber reinforced composites (U-PVAF-1) (30 wt%) were both improved. Compared with R-PVA fiber, the strength and toughness of PVA composites can be further improved with the introduction of U-PVA fiber. The tensile strength of pure PVA film is about 30.1 MPa, while the tensile strength of U-PVAF-3 (50 wt%) can reach 70.0 MPa after the self-strengthening of PVA nanofiber, and the tensile strength of U-PVAF-3 (50 wt%) is increased by about 132.6%, indicating that the self-strengthening method can greatly improve the mechanical properties of PVA film.

Tensile properties of PVA nanofiber self-reinforced transparent PVA composite film

The unique characteristics of perovskite nanocrystals (NCs) comprise excellent luminous emissions, flexibility, and remarkable optoelectronic properties. Unfortunately, the fatal drawbacks of perovskite NCs include poor stability and chemical and thermal degradation. Several studies have demonstrated that the stability of CsPbBr3 colloidal NCs could be improved through the room temperature ligand-assisted re-precipitation (LARP) method. Additionally, analysis towards CsPbBr3 NCs surface will aid in developing long-term stability of colloidal NCs based devices. To date, no comprehensive study on the surface chemistry of CsPbBr3 colloidal NCs has been attempted nor initiated.

The Surface Structure of Size-tuneable Colloidal CsPbBr3 Nanocrystals

1) A new technique for synthesis of Au nanoparticle embedded inPoly(methyl-methacrylate-PMMA) and Poly(styrene - PS) freestanding (FS) films using biomimetic templates of black plum andlemon grass leaves is introduced. 2) The black plum leaf is hydrophilic while lemongrass ishydrophobic in nature. 3) The demonstration of these microstructurally replicated surfacesfor Surface enhanced Raman scattering (SERS) and wettabilityapplications is presented. 4) The wettability of the FS films is mainly hydrophilic with angledependent on surface roughness and precursor concentration.5) Detection of 4- aminothiophenol (4-ATP), L-Aspartic Acid andChebulinic acid by the FS films using is demonstrated. Enhancementfactors of the order of 104 are achieved.

Biomimetic-templated growth of gold nanoparticle-Poly(methyl-methacrylate) and Poly(styrene) films for different applications

The future of green electronics possessing great strength and toughness proves to be a promising area of research in this technologically advanced society. This work developed the first fully bendable and malleable toughened PLA green composite by incorporating a multi-functional PHB-rubber copolymer filler that acts as an effective nucleating agent to accelerate the PLA crystallization and performs as a dynamic plasticizer to generate massive polymer chain movement. The resultant biocomposite exhibits a 24-fold and 15-fold increment in both elongation and toughness respectively while retaining its elastic modulus at > 3 GPa. Mechanism study shows the toughening effect is due to an amalgamation of massive shear yielding, crazing, and nano-cavitation in the highly-dense PLA matrix. Uniquely distinguished from the typical flexible polymer that stretches and recovers, this biocomposite is the first report of PLA that can be “bend, twist, turn and fold” at room temperature and exhibit excellent mechanical robustness even after a 180 ° bend, attributes to the highly interconnected polymer network of innumerable nano-cavitation complemented with an extensively unified fibrillar bridges. This unique trait certainly opens up a new horizon to future sustainable green electronics development.

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