Browsing by Author "Guo, Tianyu"
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- Intermolecular self-assembly of dopamine-conjugated carboxymethylcellulose and carbon nanotubes toward supertough filaments and multifunctional wearables
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2021-07-15) Guo, Tianyu; Wan, Zhangmin; Li, Dagang; Song, Junlong; Rojas, Orlando J.; Jin, YongcanThe utilization of smart textiles, mainly in the form of yarns and wovens, requires high structural toughness and flexibility. To this end, we introduce a strategy based on the intermolecular self-assembly of dopamine-conjugated carboxymethyl cellulose (DA-CMC) with carbon nanotubes (CNT). Upon coagulation in a nonsolvent, the DA-CMC/CNT suspensions readily form composite filaments by the effects of hydrogen bonding, H-pi, anion-pi, and pi-pi interactions, as demonstrated by molecular dynamic simulation. The DA-CMC/CNT filaments display super-toughness (~76.2 MJ m−3), extensibility (strain to failure of ~14.8% at 90% RH, twice that of dopamine-free analogous systems) and high electrical conductivity. Moreover, the composite filaments form conductive networks that effectively support bending, strain and compression in air or fluid media. As such, they are suitable for application in wearables devices designed for sensing and electrothermal heating. Our proposed, scalable synthesis of multifunctional filaments opens new opportunities given their electroactivity and suitability for human interfacing. - Mechanisms of Strain-Induced Interfacial Strengthening of Wet-Spun Filaments
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2022-04-13) Guo, Tianyu; Wan, Zhangmin; Yu, Yan; Chen, Hui; Wang, Zhifeng; Li, Dagang; Song, Junlong; Rojas, Orlando J.; Jin, YongcanWe investigate the mechanism of binding of dopamine-conjugated carboxymethyl cellulose (DA-CMC) with carbon nanotubes (CNTs) and the strain-induced interfacial strengthening that takes place upon wet drawing and stretching filaments produced by wet-spinning. The filaments are known for their tensile strength (as high as 972 MPa and Young modulus of 84 GPa) and electrical conductivity (241 S cm-1). The role of axial orientation in the development of interfacial interactions and structural changes, enabling shear load bearing, is studied by molecular dynamics simulation, which further reveals the elasto-plasticity of the system. We propose that the reversible torsion of vicinal molecules and DA-CMC wrapping around CNTs are the main contributions to the interfacial strengthening of the filaments. Such effects play important roles in impacting the properties of filaments, including those related to electrothermal heating and sensing. Our findings contribute to a better understanding of high aspect nanoparticle assembly and alignment to achieve high-performance filaments. - Monodispersed Renewable Particles by Cascade and Density Gradient Size Fractionation to Advance Lignin Nanotechnologies
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2024-08-22) Chen, Jingqian; Tian, Jing; Feng, Nianjie; Ning, Like; Wang, Dong; Zhao, Bin; Guo, Tianyu; Song, Junlong; Rojas, Orlando J.Control over particle size and shape heterogeneity is highly relevant to the design of photonic coatings and supracolloidal assemblies. Most developments in the area have relied on mineral and petroleum-derived polymers that achieve well-defined chemical and dimensional characteristics. Unfortunately, it is challenging to attain such control when considering renewable nanoparticles. Herein, a pathway toward selectable biobased particle size and physicochemical profiles is proposed. Specifically, lignin is fractionated, a widely available heterogeneous polymer that can be dissolved in aqueous solution, to obtain a variety of monodispersed particle fractions. A two-stage cascade and density gradient centrifugation that relieves the need for solvent pre-extraction or other pretreatments but achieves particle bins of uniform size (~60 to 860 nm and polydispersity, PDI<0.06, dynamic light scattering) along with characteristic surface chemical features is introduced. It is found that the properties and associated colloidal behavior of the particles are suitably classified in distinctive size populations, namely, i) nanoscale (50–100 nm), ii) photonic (100–300 nm) and iii) near-micron (300–1000 nm). The strong correlation that exists between size and physicochemical characteristics (molar mass, surface charge, bonding and functional groups, among others) is introduced as a powerful pathway to identify nanotechnological uses that benefit from the functionality and cost-effectiveness of biogenic particles.