Author Archives: ningyanlab

New article: Integrated emulsion separation and fog collection with functionalized Janus wood membrane for water scarcity solutions

Posted on by

A new article from Ning Yan’s lab has been published in npj Clean Water written by Kaiwen Chen, Jianyi Zhu, Cheng Hao, Haonan Zhang, Yujing Tan, Xianfu Xiao, Fengze Sun, Xuewen Han, Hui Peng, Tianyi Zhan, Jianxiong Lyu & Ning Yan.

You can find the article here.

Abstract

Global climate change has exacerbated water scarcity, while traditional water treatment technologies are often unsustainable due to high energy consumption and negative environmental impacts, posing an urgent need for a sustainable solution. This study developed a novel wood-based flexible Janus membrane coupled with a spine structure for efficient oil-water emulsion separation and fog harvesting. The Janus wood membrane showed high separation efficiency (> 99.6%), high filtration flux (water-in-oil and oil-in-water emulsions exceeded 810 L/m²·h and 747 L/m²·h, respectively), and good reusability. Additionally, the introduction of spine and conical pores significantly enhanced fog collection efficiency (19.23 kg/m²·h), expanding the application potential of Janus membranes. Moreover, this Janus wood membrane offered excellent mechanical properties, dimensional stability, mildew resistance, and environmental benefits. This study underscored the potential of Janus membranes in water management and liquid separation, providing a sustainable solution to water scarcity.

New article: Starch-based reversible adhesive: Effect of off-stoichiometric ratios on transesterification vitrimer properties

Posted on by

A new article from Ning Yan’s lab has been published in Carbohydrate Polymers written by Nicole Tratnik, Nicolas R. Tanguy, Daniel J. Davidson, Ning Yan.

You can find the article here.

Abstract

Bio-based epoxy vitrimers are gaining attention as sustainable alternatives to traditional epoxies due to renewable starting materials and recyclability, enabling material circularity. Transesterification, a dynamic bond reaction mechanism in vitrimers, relies on ample hydroxy and esters groups in the polymer network to rearrange under moderate conditions. To reduce reliance on petroleum we investigated starch, a natural feedstock rich in hydroxy groups. Ester bond densities were adjusted with an ester containing crosslinker (pentaerythritol tetrakis(3-mercaptopropionate) (PETMP)) at various epoxy to crosslinker molar ratios (1:0.7, 1:1, 1:1.25 and 1:1.5) with TEMPO as the catalyst. The reformation efficiency of the vitrimer increased to 239 % from 31 % when the ratio changed from 1:1 to 1:1.5. Essential dynamic behavioral parameters (dynamic bond exchange activation energy (Ea(d)), Arrhenius prefactor (τ0), and freezing transition temperature (Tv)) were analysed. Adding excess amount of crosslinker decreased the Tg, crosslink density, Ea(d) and Tv of the starch-based epoxy vitrimer. Adhesion tests on birch veneer found that a 1:1.5 ratio had the highest adhesion performance at 3.02 ±0.7 MPa with an adhesion recovery as high as 91 % averaging 61 +/− 23 %. These insights into density of dynamic bonds and active functional groups will contribute to developing new bio-based vitrimers with designed circularity.

New article: Reprocessable Ferulic Acid-Based Nonisocyanate Polythiourethanes and Polyurethanes with High-Performance and Shape Memory Capabilities

Posted on by

A new article from Ning Yan’s lab has been published in ACS Applied Polymer Materials written by Xiaobo Xu, Minghui Cui, Mengqiu Quan, Yuqing Wang, Genzheng Sha, Jin Zhu, Ning Yan, and Jing Chen.

You can find the article here

Abstract

The use of renewable raw materials to construct environmentally friendly, nontoxic, nonisocyanate polymer materials has been gaining attention. Here, we prepared ferulic acid epoxy (FAE) by directly reacting the lignin derivative ferulic acid with epichlorohydrin. It was used as a precursor to construct five-membered cyclic carbonate (CC) and five-membered cyclic dithiocarbonate (DTC) with CO2 and CS2, respectively. These cyclic carbonates are then cured with different amines to produce nonisocyanate polyurethanes (NIPUs) and nonisocyanate polythiourethanes (NIPTUs) with excellent properties. Ferulic acid contains a rigid aromatic ring structure, so the prepared nonisocyanate polymer materials have excellent mechanical properties, and the maximum tensile strength can reach 34.2 MPa. We compared NIPUs and NIPTUs in terms of their chemical structure, cross-link density, mechanical properties, and processing for remodeling. In addition, Due to the autoxidation of pendant sulfhydryl groups, disulfide bonds are present in the network structure of NIPTUs in addition to thionourethane. This endows NIPTUs with higher cross-link density, lower relaxation activation energy (Ea), and lower remodeling temperature (<140 °C). After thermocompression remodeling, the tensile strength of NIPTUs significantly increased due to the enhanced thermally induced formation of disulfide bonds. This study evaluates the potential for the direct synthesis of biobased aromatic NIPUs and NIPTUs based on ferulic acid, providing a simple route for the preparation of nonisocyanate polyurethanes and polythiourethanes using cyclic carbonates.

New Article: Innovative Janus wood membranes: Harnessing wood anisotropy for superior liquid separation and transport

Posted on by

A new article from Ning Yan’s lab has been published in Chemical Engineering Journal written by Kaiwen Chen, Xianfu Xiao, Cheng Hao, Fengze Sun, Haonan Zhang, Yujing Tan, Jianyi Zhu, Hui Peng, Tianyi Zhan, Jianxiong Lyu and Ning Yan.

You can find the article here

Abstract

The asymmetric wettability of Janus membranes shows promising prospects in the field of liquid transport and separation, and researchers are seeking environmentally friendly and cost-effective feedstock for fabricating these membranes. In this study, we developed two types of high-performance, flexible, and durable asymmetric Janus membranes from wood: Janus cross-section wood membrane (JCW) and Janus longitudinal-section wood membrane (JLW). Wood, being an anisotropic material stemming from its grain orientation, possesses a hierarchical porous structure that can be tailored for various practical applications. The JCW, characterized by its vertical wood channel structure and larger pore size, demonstrated superior unidirectional water transport and fog collection capabilities. Its water–oil separation efficiency reached 99.9%, with a filtration flux exceeded 3000 L/m2∙h. The JLW, featuring three-dimensional interconnected micro-nano channels and layered pathways, was particularly effective in separating oil–water emulsions. The separation efficiency of oil–water emulsions reached 99.91%, with filtration fluxes for water-in-oil and oil-in-water emulsions being as high as 500 and 700 L/m2∙h, respectively. These results underscored the potential of asymmetric wettability Janus membranes in the fields of liquid transport and separation, while also paving the way for the utilization of sustainable and eco-friendly feedstocks.

New Article: Novel Cellulosic Fiber Composites with Integrated Multi-Band Electromagnetic Interference Shielding and Energy Storage Functionalities

Posted on by

A new article from Ning Yan’s lab has been published in Nano-Micro Letters written by Xuewen Han, Cheng Hao, Yukang Peng, Han Yu, Tao Zhang, Haonan Zhang, Kaiwen Chen, Heyu Chen, Zhenxing Wang, Ning Yan & Junwen Pu.

You can find the article here

Abstract

In an era where technological advancement and sustainability converge, developing renewable materials with multifunctional integration is increasingly in demand. This study filled a crucial gap by integrating energy storage, multi-band electromagnetic interference (EMI) shielding, and structural design into bio-based materials. Specifically, conductive polymer layers were formed within the 2,2,6,6-tetramethylpiperidine-1-oxide (TEMPO)-oxidized cellulose fiber skeleton, where a mild TEMPO-mediated oxidation system was applied to endow it with abundant macropores that could be utilized as active sites (specific surface area of 105.6 m2 g−1). Benefiting from the special hierarchical porous structure of the material, the constructed cellulose fiber-derived composites can realize high areal-specific capacitance of 12.44 F cm−2 at 5 mA cm−2 and areal energy density of 3.99 mWh cm−2 (2005 mW cm−2) with an excellent stability of maintaining 90.23% after 10,000 cycles at 50 mA cm−2. Meanwhile, the composites showed a high electrical conductivity of 877.19 S m−1 and excellent EMI efficiency (> 99.99%) in multiple wavelength bands. The composite material’s EMI values exceed 100 dB across the L, S, C, and X bands, effectively shielding electromagnetic waves in daily life. The proposed strategy paves the way for utilizing bio-based materials in applications like energy storage and EMI shielding, contributing to a more sustainable future.

New Article: Cultivation of In situ foam 3D-printing: Lightweight and flexible triboelectric nanogenerators employing polyvinylidene fluoride/graphene nanocomposite foams with superior EMI shielding and thermal conductivity

Posted on by

A new article out of a collaboration with Amirjalal Jalali from Dr. Mohini Sain and Dr. Chul B Park’s labs has been published in Nano Energy written by Amirjalal Jalali, Araz Rajabi-Abhari, Haonan Zhang, Tanmay Gupta, Otavio Augusto Titton Dias, Md Akibul Islam, Tobin Filleter, Ning Yan, Mohini Sain, and Chul B Park.

A free copy of the article can be found here until January 31, 2025.

Abstract

This study explores the novel realm of foam 3D-printing, a convergence of foaming and 3D-printing techniques, with profound implications for multifunctional stretchable electronics. Through scalable in situ foam printing, lightweight and stretchable foamed polyvinylidene fluoride (PVDF)/graphene nanocomposites were successfully fabricated. By incorporating varying percentages (2, 3, 5, and 7 wt%) of graphene into PVDF, alongside a 3 wt% foaming agent for foamed 3D-printing filaments, a diverse range of filaments were fabricated. Next, employing fused filament fabrication (FFF), 3D-printed PVDF nanocomposites and nanocomposites foams were produced. Both shear and elongational rheological tests, respectively, corroborated that the incorporation of a foaming agent and graphene amplified the shear-thinning behavior and instigated strain hardening in the PVDF nanocomposite foam, rendering them viable options for foam 3D-printing. The resulting materials exhibited promising electrical and thermal conductivity attributes, as well as effective electromagnetic interference (EMI) shielding properties. The additional nanofiller content significantly augmented both electrical and thermal conductivity, further enhanced by the introduction of a cellular structure. Notably, foamed 3D-printed PVDF nanocomposites containing 7 wt% of graphene demonstrated an EMI shielding effectiveness (SE) of 36 dB distinguished by minimal reflectivity and predominant absorption characteristics. X-ray diffraction (XRD) analysis indicated that the in situ foam 3D-printing facilitates the formation of the β-phase. The printed specimens were deployed as the tribonegative element in the Triboelectric Nanogenerator (TENG) system. The fabricated TENG displayed notable efficiency, as evidenced by the foamed 3D-printed PVDF, which generated an output voltage of 270 V and a current of 5 μA, successfully illuminating 80 Light Emitting Diode (LED) lights. Meanwhile, the 3D-printed nanocomposite foams with 3 wt% nanofiller exhibited superior performance, achieving an output voltage of 550 V and a current of 11 μA. This investigation underscores the potential of the in situ foam 3D-printing for the development of advanced lightweight and flexible energy storage devices.

New Article: Highly Conducting and Ultra-Stretchable Wearable Ionic Liquid-Free Transducer for Wireless Monitoring of Physical Motions

Posted on by

A new article from Ning Yan’s lab has been published in Macromolecular Rapid Communications written by Nicolas R. Tanguy, Araz Rajabi-Abhari, Eric Williams-Linera, Zheyuan Miao, Nicole Tratnik, Xiao Zhang, Cheng Hao, Alvin Virya, Ning Yan, and Ronan Le Lagadec.

You can find the article here

Abstract

Wearable strain transducers are poised to transform the field of healthcare owing to the promise of personalized devices capable of real-time collection of human physiological health indicators. For instance, monitoring patients’ progress following injury and/or surgery during physiotherapy is crucial but rarely performed outside clinics. Herein, multifunctional liquid-free ionic elastomers are designed through the volume effect and the formation of dynamic hydrogen bond networks between polyvinyl alcohol (PVA) and weak acids (phosphoric acid, phytic acid, formic acid, citric acid). An ultra-stretchable (4600% strain), highly conducting (10 mS cm-1), self-repairable (77% of initial strain), and adhesive ionic elastomer is obtained at high loadings of phytic acid (4:1 weight to PVA). Moreover, the elastomer displayed durable performances, with intact mechanical properties after a year of storage. The elastomer is used as a transducer to monitor human motions in a device comprising an ESP32-based development board. The device detected walking and/or running biomechanics and communicated motion-sensing data (i.e., amplitude, frequency) wirelessly. The reported technology can also be applied to other body parts to monitor recovery after injury and/or surgery and inform practitioners of motion biomechanics remotely and in real time to increase convalescence effectiveness, reduce clinic appointments, and prevent injuries.