Patterning And Preparation Of Water-based Ink Based On NFCs/CdS Quantum Dots Nanocomposites

3D printing is a most potential additive manufacturing system and has aroused many attentions due to its accurate structures control. It is reported that nanocellulose was employed in the bio-medical fields based on the 3D bio-printing. Nanocellulose which derived from abundant plants was one of the most potential polymers due to its high modulus, high tensile strength, low cost, low weight, bio-compatibility, biodegradability and good-filming. Cd S quantum dots, which are typical II–IV narrow-band semiconductors, have received much attention in terms of their extraordinary photoluminescent performance according to the quantum confinement effect, making them applicable as bio-labeling and anti-counterfeiting fields. Integrating NFCs’ s good-filming property with Cd S quantum dots’ s excellent tunable photoluminescence to fabricate functional water-based ink, NFCs may find a promising application in the anti-counterfeiting, bio-labeling and 3D printing.In this study, influence of the size of the Cd S quantum dots on the photoluminescence of the NFCs/Cd S quantum dots nanocomposites was investigated by controlling –COOH/Cd2+, the carboxylate contents of NFCs, the adding time of Na2 S solutions and the ultrasound maturing time. The mechanism of the compounding reaction was discussed by FTIR, 13C-NMR and XRD spectrum. Influence of the carboxylate contents of NFCs, concentration of NFCs/Cd S quantum dots nanocomposites and additives on the performance of the water-based ink was discussed. UV-curing waterborne ink was fabricated by compounding the polyacrylate and NFCs/Cd S quantum dots nanocomposites. 3D printing resolution was investigated by fabricating patterns with different structures. The photoluminescence of the patterns was studied by CLSM. The results are showed as follows:1. The influence of-COOH/Cd2+,-COOH contents of NFCs, the adding time of Na2 S solutions and the ultrasound maturing time on the size of Cd S quantum dots were discussed. The results showed as follows:(1) when the-COOH/Cd2+ was 2:1,1:1,1:2, the size of Cd S quantum dots was 4.86nm、4.58 nm and 4.27 nm respectively;(2) the average size of Cd S quantum dots was 3.3nm with different carboxylate contents of NFCs;(3) when the adding time of Na2 S solutions was 10 min,20min,30 min and 40 min,the size of Cd S quantum dots was 4.59 nm,4.86 nm,4.01 nm and 3.76 nm respectively;(4) when the ultrasound maturing time was 40 min,60min,80 min and 100 min,the size of Cd S quantum dots was 3.68 nm,5.34 nm,3.96 nm and 3.44 nm respectively。2. The influence of-COOH/Cd2+, the carboxylate contents of NFCs, the adding time of Na2 S solutions and the ultrasound maturing time on the photoluminescence of NFCs/Cd S quantum dots nanocomposites were discussed. The results of PL spectrum run as followings:(1) With the-COOH/Cd2+ decreased from 2 to 1, the wavelength of NFCs/Cd S quantum dots nanocomposites shift from 613 nm to 650 nm. There was a broad emission peak at the range of 500-625 nm with the-COOH/Cd2+ of 0.5;(2) With the carboxylate contents of NFCs increased from 1.32mmol/g to 1.63mmol/g, the wavelength of NFCs/Cd S quantum dots nanocomposites shift from 534 nm to 529 nm, then shift to 535 nm and last shift to 528nm;(3) With the adding time of Na2 S solutions increased from 10 min to 40 min,the wavelength of nanocomposites shift from 622 nmto 633nm then shift left to 615 nm and finally shift to 604nm;(4) With the ultrasound maturing time increased from 40 min to 100 min,the wavelength of nanocomposites shift from 563 nm to 653 nm then shift to 579 nm and finally shift to 556 nm. The photographs of nanocomposites under irradiation of UV lights were in accordance with the PL spectrum.3. The reaction mechanism was investigated by FTIR, 13C-NMR and XRD spectrum. FTIR analysis show that C=O peaks at 1610cm-1 was effected by the compounding Cd S quantum and the 13C-NMR spectrum shows that peak for C6 position’s C=O at 168-170 ppm region was also effected by the Cd S quantum dots, and the peak has been widen. Therefore the carboxylate was the reaction sites of the Cd S quantum dots.4. The influence of carboxylate contents of NFCs, the concentration of the nanocomposites and additives on the properties of waterborne ink based on the NFCs/Cd S quantum dots nanocomposites was discussed. The results showed that the viscosity of NFCs/Cd S quantum dots nanocomposites was 2-20 mpas with different carboxylate contents of NFCs and the concentration of the nanocomposites. The viscosity of waterborne ink based on NFCs/Cd S quantum dots nanocomposites was not be influenced by adding SDBS. And the ink could dispersed well on paper with SDBS. The waterborne ink was stable and could remain stable for a long time from its results of Zeta potential.5. UV-curing waterborne ink was fabricated by compounding the polyacrylate with NFCs/Cd S quantum dots nanocomposites. The patterns with different sizes were observed by CLSM. The results of CLSM showed that the patterns had excellent photoluminescence.