Heger Julian E, Reitenbach Julija, Kreuzer Lucas P, Pan Guangjiu, Tian Ting, Huber Linus F, Li Nian, Sochor Benedikt, Schwartzkopf Matthias, Roth Stephan V, Koutsioubas Alexandros, Müller-Buschbaum Peter
Department of Physics, Chair for Functional Materials, TUM School of Natural Sciences, Technical University of Munich, James-Franck-Str. 1, Garching 85748 Germany.
School of Physics, University of Electronic Science and Technology of China, Chengdu 610106, China.
JACS Au. 2025 Mar 19;5(4):1894-1902. doi: 10.1021/jacsau.5c00097. eCollection 2025 Apr 28.
The whey protein beta-lactoglobulin (β-lg) is used as a biotemplate for the water-based synthesis of nanostructured and foam-like titania films based on its variation in supramolecular structure when denatured at different pH values. Acting as a matrix, β-lg is mixed with the water-soluble titania precursor Ti(IV) bis(ammonium lactate)dihydroxide (TiBALDh) to promote biotemplated titania precipitation. Since TiBALDh is in chemical equilibrium with anatase titania nanoparticles and Ti(IV)-lactate complexes, and this equilibrium shifts with varying pH, the influence of the pH value on the final film morphology becomes essential. This work investigates this influence for three pH values: pH 7, pH 5, i.e., close to the isoelectric point of β-lg, and pH 2. Spray coating, a method of industrial relevance, is used to fabricate biohybrid β-lg:TiBALDh foam-like films. The obtained films are calcined to combust biotemplate β-lg and achieve nanostructured titania films. To understand the influence of pH on the film morphology, grazing-incidence small-angle and wide-angle X-ray scattering (GISAXS/GIWAXS) and grazing-incidence small-angle neutron scattering (GISANS), in combination with scanning electron microscopy (SEM), are applied to both the biohybrid and biotemplated titania films. With these techniques, information about domain sizes, porosity, and crystal structure is obtained with high statistical significance. Fourier-transform infrared spectroscopy (FTIR) probes the interaction of TiBALDh and β-lg on the molecular level as a function of pH. The results underline pH as a suitable tool for tuning the morphology in biotemplated titania films.
乳清蛋白β-乳球蛋白（β-lg）基于其在不同pH值下变性时超分子结构的变化，被用作水基合成纳米结构和泡沫状二氧化钛薄膜的生物模板。作为基质，β-lg与水溶性二氧化钛前驱体二羟基双（乳酸铵）钛（IV）（TiBALDh）混合，以促进生物模板化二氧化钛沉淀。由于TiBALDh与锐钛矿型二氧化钛纳米颗粒和Ti（IV）-乳酸配合物处于化学平衡，且这种平衡随pH值变化而移动，因此pH值对最终薄膜形态的影响至关重要。这项工作研究了三个pH值（pH 7、pH 5，即接近β-lg的等电点和pH 2）的这种影响。采用具有工业相关性的喷涂方法制备生物杂化β-lg:TiBALDh泡沫状薄膜。将所得薄膜煅烧以燃烧生物模板β-lg，从而获得纳米结构的二氧化钛薄膜。为了了解pH对薄膜形态的影响，将掠入射小角和广角X射线散射（GISAXS/GIWAXS）以及掠入射小角中子散射（GISANS）与扫描电子显微镜（SEM）相结合，应用于生物杂化和生物模板化二氧化钛薄膜。通过这些技术，可以获得具有高统计显著性的关于畴尺寸、孔隙率和晶体结构的信息。傅里叶变换红外光谱（FTIR）在分子水平上探测TiBALDh和β-lg作为pH函数的相互作用。结果强调pH是调节生物模板化二氧化钛薄膜形态的合适工具。
