TY - JOUR

T1 - Chemical versus physical grafting of photoluminescent amino-functional carbon dots onto transparent nematic nanocellulose gels and aerogels

AU - Quraishi, Sakeena

AU - Plappert, Sven F.

AU - Grießer, Thomas

AU - Gindl-Altmutter, Wolfgang

AU - Liebner, Falk W.

PY - 2019/9/30

Y1 - 2019/9/30

N2 - Transparent matrices of low refractive index are promising carriers for photoluminescent nanoparticles targeting true volumetric 3D display applications. Complementation of transparency with a highly open-porous nanomorphology renders respective hybrid gels and aerogels additionally attractive for liquid and gas detection devices. Herein, we present virtually fully bio-based hybrids obtained by decorating highly transparent, nematically ordered gels and aerogels (15–20 mg cm−3) from carboxylated and individualized cellulose nanofibers (i-CNF) with amino-functional photoluminescent carbon dots (CD). The latter were obtained by microwave-assisted hydrothermolysis of lemon juice. As the way of anchoring the CDs onto the large internal surface of the porous i-CNF scaffolds (320 m2 g−1) has a great impact on the final properties of the hybrid materials including leaching of CDs and reusability of the hybrid, this study assessed the respective pros and cons of a physical and chemical bonding approach. The results confirmed the superiority of covalent grafting. Aqueous carbodiimide coupling of amino-functionalized CDs afforded higher yields of CDs in the final hybrid aerogels, distinctly higher specific surface values (491 m2 g−1) and slightly enhanced mechanical properties while the high light transmittance and nanomorphology of the i-CNF precursor alcogels is virtually not compromised. Therefore, we conclude that the luminescent i-CNF/CD-chem hybrid materials of this study are promising candidates for environmentally friendly chemical sensing and volumetric display applications.

AB - Transparent matrices of low refractive index are promising carriers for photoluminescent nanoparticles targeting true volumetric 3D display applications. Complementation of transparency with a highly open-porous nanomorphology renders respective hybrid gels and aerogels additionally attractive for liquid and gas detection devices. Herein, we present virtually fully bio-based hybrids obtained by decorating highly transparent, nematically ordered gels and aerogels (15–20 mg cm−3) from carboxylated and individualized cellulose nanofibers (i-CNF) with amino-functional photoluminescent carbon dots (CD). The latter were obtained by microwave-assisted hydrothermolysis of lemon juice. As the way of anchoring the CDs onto the large internal surface of the porous i-CNF scaffolds (320 m2 g−1) has a great impact on the final properties of the hybrid materials including leaching of CDs and reusability of the hybrid, this study assessed the respective pros and cons of a physical and chemical bonding approach. The results confirmed the superiority of covalent grafting. Aqueous carbodiimide coupling of amino-functionalized CDs afforded higher yields of CDs in the final hybrid aerogels, distinctly higher specific surface values (491 m2 g−1) and slightly enhanced mechanical properties while the high light transmittance and nanomorphology of the i-CNF precursor alcogels is virtually not compromised. Therefore, we conclude that the luminescent i-CNF/CD-chem hybrid materials of this study are promising candidates for environmentally friendly chemical sensing and volumetric display applications.

KW - Aerogels

KW - Carbon dots

KW - Cellulose nanofibers

KW - Hybrid

KW - Nanocellulose

KW - Photoluminescence

UR - http://www.scopus.com/inward/record.url?scp=85069453665&partnerID=8YFLogxK

U2 - 10.1007/s10570-019-02619-2

DO - 10.1007/s10570-019-02619-2

M3 - Article

AN - SCOPUS:85069453665

VL - 26.2019

SP - 7781

EP - 7796

JO - Cellulose

JF - Cellulose

SN - 0969-0239

IS - 30 September

ER -