Highly regioselective surface acetylation of cellulose and shaped cellulose constructs in the gas-phase

Gas-phase acylation of cellulose is an attractive method for modifying the surface properties of cellulosics. However, little is known concerning the regioselectivity of the chemistry, in terms of which cellulose positions are preferentially acylated and if acylation can be restricted to the surface, preserving crystallinities/morphologies. Consequently, we reexplore simple gas-phase acetylation of modern-day cellulosic building blocks – cellulose nanocrystals, pulps, regenerated fibre and aerogels. The gas-phase acetylation is shown to be highly regioselective for the C6-OH, is further supported with computational modelling. This contrasts with liquid-state acetylation, highlighting that the gas-phase chemistry is much more controllable, yet with similar kinetics to the uncatalyzed liquid-phase reactions. Furthermore, this method preserves both the native crystalline structure of cellulose and the supramolecular morphologies of even delicate cellulosic constructs (aerogel exhibiting retention of chiral cholesteric liquid crystalline phases). Therefore, we are convinced that this methodology will lead to more rapid adoption of precisely tailored and cellulosic materials

Enhanced Reactivity in Surface-Confined Water of Hierarchically Structured Polymers

The remarkable efficiency of biological chemical reactions is the result of evolution and many of these reactions are promoted by confined water. This has inspired significant research endeavors exploiting the potential of this special water in chemistry. However, these systems are so far limited to complex artificial solids or biphasic systems and small molecules as reactants. Here, we show that the intrinsically present surface-confined water in hierarchically structured biopolymers can be used as nanomedium to promote chemical reactions. We found in the example of cellulose fibers that confined water was actively involved in the reaction mechanism and facilitated the surface acetylation of the fiber, increasing reaction kinetics, efficiency and regioselectivity. Our findings can be regarded as proof-of-principle that the hydration layer in nanoporous polymers can be exploited as medium to promote chemical reactions at their surface. This concept can likely be extended to other polymers and various reaction systems. <br>

Enhanced Reactivity in Surface-Confined Water of Hierarchically Structured Polymers

The remarkable efficiency of biological chemical reactions is the result of evolution and many of these reactions are promoted by confined water. This has inspired significant research endeavors exploiting the potential of this special water in chemistry. However, these systems are so far limited to complex artificial solids or biphasic systems and small molecules as reactants. Here, we show that the intrinsically present surface-confined water in hierarchically structured biopolymers can be used as nanomedium to promote chemical reactions. We found in the example of cellulose fibers that confined water was actively involved in the reaction mechanism and facilitated the surface acetylation of the fiber, increasing reaction kinetics, efficiency and regioselectivity. Our findings can be regarded as proof-of-principle that the hydration layer in nanoporous polymers can be exploited as medium to promote chemical reactions at their surface. This concept can likely be extended to other polymers and various reaction systems. <br>

Enhanced Reactivity in Surface-Confined Water of Hierarchically Structured Polymers

The remarkable efficiency of biological chemical reactions is the result of evolution and many of these reactions are promoted by confined water. This has inspired significant research endeavors exploiting the potential of this special water in chemistry. However, these systems are so far limited to complex artificial solids or biphasic systems and small molecules as reactants. Here, we show that the intrinsically present surface-confined water in hierarchically structured biopolymers can be used as nanomedium to promote chemical reactions. We found in the example of cellulose fibers that confined water was actively involved in the reaction mechanism and facilitated the surface acetylation of the fiber, increasing reaction kinetics, efficiency and regioselectivity. Our findings can be regarded as proof-of-principle that the hydration layer in nanoporous polymers can be exploited as medium to promote chemical reactions at their surface. This concept can likely be extended to other polymers and various reaction systems. <br>

Moderate surface acetylation of nanofibrillated cellulose for the improvement of paper strength and barrier properties

This study evaluated the effect of using acetylated nanofibrillated cellulose (ANFC) and acetylated pulp (AP) fibers to modify strength and barrier properties of paper.