Covalent functionalization of solid cellulose by divergent synthesis of chemically active dendrons
2018
Anavi, Daniel | Popowski, Yanay | Slor, Gadi | Segal, Merav | Frid, Liat | Amir, Roey J. | Amirav, Aviv | Amir, Elizabeth
Covalent surface modification of solid cellulose with well‐defined and chemically reactive dendrons is introduced as a platform for cellulose grafting with functional materials. Surface functionalization with a first generation dendron is achieved by esterification employing bifunctional molecules based on 2,2‐bis(hydroxymethyl) propionic acid (bis‐MPA) under mild conditions and short reaction times. The activated cellulose surface displays hydrophobic properties and contains two reactive alkene end‐groups per graft, which are used for covalent binding to active agents, as demonstrated by selective functionalization of the modified cellulose with fluorescent dye via photopatterning. The number of active end‐groups on the surface of cellulose is multiplied by divergent solid‐state synthesis of second and third generation dendrons having four and eight reactive sites per dendron, respectively. The dendrons are assembled in only few hours by a sequence of thiol‐ene/esterification reactions. The ability to accurately control the number of binding sites on the surface of cellulose allows fine tuning of the surface properties, as shown by the attachment of hydrophobic small molecules to the dendronized cellulose. The first, second and third generation dendrons allow preparing surfaces with increasing hydrophobicities; second and third generation dendrons functionalized with small perfluoroalkyl molecule display superhydrophobic properties. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 2103–2114
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