Milkova Viktoria
Institute of Physical Chemistry 'Acad. Rostislaw. Kaischew', 1113 Sofia, Bulgaria.
Polymers (Basel). 2023 Sep 14;15(18):3766. doi: 10.3390/polym15183766.
Negatively charged carbon dots (Cdots) were successfully impregnated into chitosan/alginate film formed on model colloidal particles as a result of the attractive interactions with the chitosan molecules. The electrical properties of the produced films were studied by electrokinetic spectroscopy. In this study, the electric light scattering method was applied for first the time for the investigation of suspensions of carbon-based structures. The electro-optical behavior for the suspension of polymer-coated particles showed that the electric polarizability of the particle-covered layer from alginate was significantly higher compared to that of the layer from chitosan due to the higher charge density of alginate. The presence of a low concentration of Cdots in the film results in partial charge screening. It was confirmed that the polarizability of counterions with lower mobility along the adsorbed polyion chains was responsible for the registered electro-optical effect from the suspension of polymer-coated particles and that the participation of diffuse H counterions of Cdots in the creation of the electro-optical effect was negligible. The observed oscillation behavior in the evolution of the film thickness was interpreted through the participation of compensatory effects due to the additional adsorption/desorption of polyelectrolyte complexes from the film surface. The concentration of Cdots in the film was determined, and the loaded amount was ca. 6.6 µg/mL per layer.
由于与壳聚糖分子之间的吸引相互作用，带负电荷的碳点（Cdots）成功地浸渍到在模型胶体颗粒上形成的壳聚糖/藻酸盐薄膜中。通过电动光谱研究了所制备薄膜的电学性质。在本研究中，首次应用电光散射法来研究碳基结构的悬浮液。聚合物包覆颗粒悬浮液的电光行为表明，由于藻酸盐的电荷密度较高，藻酸盐包覆层的颗粒电极化率明显高于壳聚糖包覆层。薄膜中低浓度Cdots的存在导致部分电荷屏蔽。证实了沿吸附的聚离子链迁移率较低的抗衡离子的极化率是聚合物包覆颗粒悬浮液记录的电光效应的原因，并且Cdots的扩散H抗衡离子对电光效应的产生贡献可忽略不计。通过薄膜表面聚电解质复合物的额外吸附/解吸引起的补偿效应的参与，解释了观察到的薄膜厚度演变中的振荡行为。测定了薄膜中Cdots的浓度，每层负载量约为6.6μg/mL。
