Department of Chemical Engineering, Lakehead University, Thunder Bay, ON, Canada.
Laboratory of Natural Materials Technology, Åbo Akademi University, Turku, Finland.
ACS Appl Mater Interfaces. 2021 Jun 9;13(22):26308-26317. doi: 10.1021/acsami.1c03496. Epub 2021 May 27.
Lignin is the richest source of renewable aromatics and has immense potential for replacing synthetic chemicals. The limited functionality of lignin is, however, challenging for its potential use, which motivates research for creating advanced functional lignin-derived materials. Here, we present an aqueous-based acid precipitation method for preparing functional lignin nanoparticles (LNPs) from carboxymethylated or carboxypentylated lignin. We observe that the longer grafted side chains of carboxypentylated lignin allow for the formation of larger LNPs. The functional nanoparticles have high tolerance against salt and aging time and well-controlled size distribution with ≤ 60 nm over a pH range of 5-11. We further investigate the layer-by-layer (LbL) assembly of the LNPs and poly(allylamine hydrochloride) (PAH) using a stagnation point adsorption reflectometry (SPAR) and quartz crystal microbalance with dissipation (QCM-D). Results demonstrate that LNPs made of carboxypentylated lignin (i.e., PLNPs with the adsorbed mass of 3.02 mg/m) form a more packed and thicker adlayer onto the PAH surface compared to those made of carboxymethylated lignin (i.e., CLNPs with the adsorbed mass of 2.51 mg/m). The theoretical flux, , and initial rate of adsorption, (dΓ/d), analyses confirm that 22% of PLNPs and 20% of CLNPs arriving at the PAH surface are adsorbed. The present study provides a feasible platform for engineering LNPs with a tunable size and adsorption behavior, which can be adapted in bionanomaterial production.
木质素是可再生芳烃最丰富的来源，具有替代合成化学品的巨大潜力。然而，木质素的功能有限，限制了其潜在用途，这促使人们研究创造先进的功能性木质素衍生材料。在这里，我们提出了一种基于水的酸沉淀法，用于从羧甲基化或羧戊基化木质素制备功能性木质素纳米颗粒（LNPs）。我们观察到，羧戊基化木质素上较长的接枝侧链允许形成更大的 LNPs。功能性纳米颗粒对盐和老化时间具有高耐受性，并且在 pH 值为 5-11 的范围内具有良好控制的尺寸分布，≤60nm。我们进一步研究了 LNPs 和聚烯丙基胺盐酸盐（PAH）的层层（LbL）组装，使用停滞点吸附反射计（SPAR）和石英晶体微天平耗散（QCM-D）。结果表明，由羧戊基化木质素制成的 LNPs（即吸附质量为 3.02mg/m 的 PLNPs）在 PAH 表面上形成更致密和更厚的吸附层，而由羧甲基化木质素制成的 LNPs（即吸附质量为 2.51mg/m 的 CLNPs）则形成更薄的吸附层。理论通量，和初始吸附速率，（dΓ/d）分析证实，22%的 PLNPs 和 20%的 CLNPs 到达 PAH 表面被吸附。本研究为工程 LNPs 提供了一个可行的平台，可调节其尺寸和吸附行为，可适应生物纳米材料的生产。
