Faculty of Informatics, ELTE Eötvös Loránd University, 1053, Budapest, Hungary.
Institute of Cellulose and Paper Technology, Celltech-Paper Ltd., 9634, Lócs, Hungary.
Sci Rep. 2022 Aug 25;12(1):14475. doi: 10.1038/s41598-022-18749-w.
Photoabsorption properties of cellulose fibres under continuous and modulated irradiation were investigated in situ by the use of reversed double-beam photoacoustic spectroscopy (RDB-PAS). This photoacoustic (PA) measurement enabled observation of ultraviolet- and visible light-induced, electron trap filling, and reductive change on the surface of the fibres. Energy-resolved measurements and analysis of the kinetics of photoinduced de-excitation suggested that electrons that accumulated in the different cellulose crystalline phases had moderate reactivity toward molecular oxygen. Saturation limits of the intensities of the PA and RDB-PAS signals under de-aerated conditions in the presence of surface-adsorbed methanol were estimated for softwood and hardwood cellulose samples. The results suggest that the RDB-PAS technique is a feasible method for the estimation of the electron trap distribution, which is a potential measure of the density of crystalline cellulose defects.
采用反双光束光声光谱法（RDB-PAS）原位研究了纤维素纤维在连续和调制辐照下的光吸收特性。这种光声（PA）测量可以观察到紫外光和可见光诱导的、电子陷阱填充和纤维表面的还原变化。对光诱导去激发动力学的能量分辨测量和分析表明，在有氧条件下，不同纤维素晶相中积累的电子对分子氧具有中等的反应性。在有氧条件下，用表面吸附的甲醇对软木和硬木纤维素样品进行脱气，估计了 PA 和 RDB-PAS 信号强度的饱和极限。结果表明，RDB-PAS 技术是一种估算电子陷阱分布的可行方法，而电子陷阱分布是纤维素晶体缺陷密度的潜在衡量标准。
