Preparation Of Cellulose-Based Marbles And Its Gas Detection

Liquid marbles,as particle-armored droplets,have potential applications in microreactors,biomedicine,controlled release and gas detection.In order to better stabilize liquid marbles,silane or fluorine-containing reagents are usually used to modify particles,making liquid marbles is not environmentally friendly.In addition,the mechanical stability of liquid marbles under external impact is poor,and it is difficult to exist stably for a long time.To enhance the biocompatibility and mechanical strength of liquid marbles,cellulose-based liquid marbles with biocompatibility were constructed by preparing cellulose acetate particles（CA）and 3-allyloxy-2-hydroxypropyl cellulose（AHP-cellulose）.The cellulose-based hydrogel marbles with excellent mechanical stability were prepared by blue-light-irradiated polymerization.The impact resistance,bounce and compression properties of cellulose-based liquid marbles and hydrogel marbles were studied,and the application of cellulose-based marbles in the field of gas detection was explored.The specific research contents are as follows:Firstly,CA and AHP-cellulose were synthesized by esterification and etherification of cellulose from bamboo dissolving pulp.The three acetyl bands at 1751,1375 and 1236 cm^-1 in the FTIR spectra correspond to C=O stretching,C-CH₃ bending and C-O stretching vibration,respectively,confirming the successful synthesis of CA.The C=C peak at 1545 cm^-1 in the FTIR spectrum of AHP-cellulose confirmed its successful synthesis.¹H NMR results showed that the degree of substitution of CA and AHP-cellulose were 2.65 and 1.91,respectively.XRD test showed that both CA and AHP-cellulose had cellulose II diffraction structure.TG tests showed that the thermal stability of AHP-cellulose was lower than that of cellulose,while CA was better than cellulose due to the presence of acetyl group.The apparent contact angle tests showed that CA had good hydrophobicity with a contact angle of 134.5±2.4°,and AHP-cellulose had hydrophilicity with a contact angle of less than 10°.The biocompatibility tests confirmed that CA and AHP-cellulose had good biocompatibility,and the cell survival rates were 86.07%and 72.23%,respectively.Secondly,cellulose-based liquid marbles with core-shell structure were constructed by using CA as hydrophobic shell and AHP-cellulose aqueous solution as core droplets.The effective surface tension of cellulose-based liquid marbles is 66.3 m N/m.The impact resistance and bounce performance of liquid marbles were studied by dropping marbles from a certain height.The results show that the height required for the rupture of 1%cellulose-based liquid marbles is 70 mm,which is 2.8 times higher than that of water marbles（25 mm）.With the increase of AHP-cellulose concentration,the higher the height required for the rupture of cellulose-based liquid marbles,the better the impact resistance.When released from a height of 60 mm,the bounce height of 1%cellulose-based liquid marbles was 0.7 mm,indicating that cellulose-based liquid marbles had good bounce performance.With the increase of the concentration of AHP-cellulose,the bounce height of cellulose-based liquid marbles showed an increasing trend.At 7%,the maximum bounce height achieved2.6 mm.The introduction of glycerol and phenolphthalein indicator in AHP-cellulose aqueous solution can significantly inhibit the volatilization of water,and prepared cellulose-based liquid marbles are stable to detect alkaline gases,such as ammonia.Finally,to further improve the mechanical strength and long-term stable detection of cellulose-based liquid marbles,cellulose-based liquid marbles with blue light initiator LAP were rapidly polymerized within 5 s of blue light irradiation to prepare cellulose-based hydrogel marbles.The cellulose-based hydrogel marbles have good biocompatibility,and the cell survival rate reaches 77.03%.The impact resistance and bounce properties of cellulose-based hydrogel marbles with different AHP-cellulose concentrations were characterized,and the application of cellulose-based hydrogel marbles in the field of gas detection was explored.The results show that the mechanical strength of cellulose-based hydrogel marbles is better than that of liquid marbles.The 3%cellulose-based hydrogel marbles remain intact even after falling from a height of 50 m.The cellulose-based hydrogel marble can bounce up to 25.5 mm when released from a height of 60 mm,which is 881%higher than liquid marble（2.6 mm）.Hydrogel marbles could detect various alkaline ammonia and amine gases.Hydrogel marble has long-term stability to continuously monitor ammonia gas.The robust cellulose-based hydrogel marble with high mechanical stability represents a new strategy and approach to gas detection in complex environments,and it could be a strong contender for gas sensors in chemical and environmental engineering.