Aerogels from Cellulose Phosphates of Low Degree of Substitution: A TBAF center dot H2O/DMSO Based Approach

authors	Schimper, CB; Pachschwoell, PS; Hettegger, H; Neouze, MA; Nedelec, JM; Wendland, M; Rosenau, T; Liebner, F
nationality	International
journal	MOLECULES
author keywords	cellulose phosphate; cellulose phosphate aerogel; interconnected porosity; supercritical carbon dioxide; tetrabutylammonium fluoride; TBAF; DMSO
keywords	BACTERIAL CELLULOSE; FIBERS; REINFORCEMENT; PYROLYSIS; SCAFFOLDS
abstract	Biopolymer aerogels of appropriate open-porous morphology, nanotopology, surface chemistry, and mechanical properties can be promising cell scaffolding materials. Here, we report a facile approach towards the preparation of cellulose phosphate aerogels from two types of cellulosic source materials. Since high degrees of phosphorylation would afford water-soluble products inappropriate for cell scaffolding, products of low DSP (ca. 0.2) were prepared by a heterogeneous approach. Aiming at both i) full preservation of chemical integrity of cellulose during dissolution and ii) utilization of specific phase separation mechanisms upon coagulation of cellulose, TBAFH(>2)O/DMSO was employed as a non-derivatizing solvent. Sequential dissolution of cellulose phosphates, casting, coagulation, solvent exchange, and scCO(2) drying afforded lightweight, nano-porous aerogels. Compared to their non-derivatized counterparts, cellulose phosphate aerogels are less sensitive towards shrinking during solvent exchange. This is presumably due to electrostatic repulsion and translates into faster scCO(2) drying. The low DSP values have no negative impact on pore size distribution, specific surface (S-BET <= 310 m(2) g(-1)), porosity (Pi 95.5-97 vol.%), or stiffness (E rho <= 211 MPa cm(3) g(-1)). Considering the sterilization capabilities of scCO(2), existing templating opportunities to afford dual-porous scaffolds and the good hemocompatibility of phosphorylated cellulose, TBAFH(2)O/DMSO can be regarded a promising solvent system for the manufacture of cell scaffolding materials.
publisher	MDPI
isbn	1420-3049
year published	2020
volume	25
issue	7
digital object identifier (doi)	10.3390/molecules25071695
web of science category	Biochemistry & Molecular Biology; Chemistry, Multidisciplinary
subject category	Biochemistry & Molecular Biology; Chemistry
unique article identifier	WOS:000531833400220