Du Ruiling, Fielding Lee A
Department of Materials, School of Natural Sciences, University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
Henry Royce Institute, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
Soft Matter. 2023 Mar 15;19(11):2074-2081. doi: 10.1039/d2sm01534j.
This paper reports a generic method to prepare polymer nanoparticle-based complex coacervate (PNCC) hydrogels by employing rationally designed nanogels synthesised by reversible addition-fragmentation chain-transfer (RAFT)-mediated polymerisation-induced self-assembly (PISA). Specifically, a poly(potassium 3-sulfopropyl methacrylate) (PKSPMA) macromolecular chain-transfer agent (macro-CTA) was synthesised RAFT solution polymerisation followed by chain-extension with a statistical copolymer of benzyl methacrylate (BzMA) and methacrylic acid (MAA) at pH 2. Thus, pH-responsive nanoparticles (NPs) comprising a hydrophobic polyacid core-forming block and a sulfonate-functional stabiliser block were formed. With the introduction of methacrylic acid into the core of the NPs, they become swollen with increasing pH, as judged by dynamic light scattering (DLS), indicating nanogel-type behaviour. PNCC hydrogels were prepared by simply mixing the PISA-derived nanogels and cationic branched polyethyleneimine (bPEI) at 20% w/w. In the absence of MAA in the core of the NPs, gel formation was not observed. The mass ratio between the nanogels and bPEI affected resulting hydrogel strength and a mixture of bPEI and PKSPMA-P(BzMA--MAA) NPs with a mass ratio of 0.14 at pH ∼7 resulted in a hydrogel with a storage modulus of approximately 2000 Pa, as determined by oscillatory rheology. This PNCC hydrogel was shear-thinning and injectable, with recovery of gel strength occurring rapidly after the removal of shear.
本文报道了一种通用方法，通过采用由可逆加成-断裂链转移（RAFT）介导的聚合诱导自组装（PISA）合成的合理设计的纳米凝胶来制备基于聚合物纳米颗粒的复合凝聚层（PNCC）水凝胶。具体而言，通过RAFT溶液聚合合成了聚（3-磺丙基甲基丙烯酸钾）（PKSPMA）大分子链转移剂（宏观CTA），随后在pH为2的条件下用甲基丙烯酸苄酯（BzMA）和甲基丙烯酸（MAA）的统计共聚物进行链延伸。由此，形成了包含疏水性聚酸核形成嵌段和磺酸盐官能化稳定剂嵌段的pH响应性纳米颗粒（NPs）。通过动态光散射（DLS）判断，随着MAA引入NPs的核中，它们随着pH值的升高而膨胀，表明具有纳米凝胶型行为。通过简单地将PISA衍生的纳米凝胶与阳离子支化聚乙烯亚胺（bPEI）以20% w/w的比例混合来制备PNCC水凝胶。在NPs的核中不存在MAA的情况下，未观察到凝胶形成。纳米凝胶与bPEI之间的质量比影响所得水凝胶的强度，在pH约为7时，bPEI与PKSPMA-P（BzMA-MAA） NPs质量比为0.14的混合物产生了储能模量约为2000 Pa的水凝胶，这是通过振荡流变学测定的。这种PNCC水凝胶具有剪切变稀和可注射性，在去除剪切力后凝胶强度迅速恢复。
