| The rod-like biomass particles,mainly cellulose nanocrystals(CNC)and chitin nanocrystals(Ch NC),have high chemical activity,renewable and biocompatibility,and have attracted much attention in the fields of assembly structure color,degradable materials,and biomedicine.In recent research results,the chiral assembly and achiral assembly structures show unprecedented application potential in anti-counterfeiting,polarized light,and other fields because of their significant controllable structural color.In particular,the achiral assembly membranes also have the ability of virtual state transition luminescence with high quantum efficiency,and their multi-level anti-counterfeiting ability has broad application prospects in the field of optical sensing.However,the rod-like nanocrystals in the assembled membranes are mainly connected by hydrogen bonds and lack of energy absorbing dissipative phase,which makes the brittleness of such materials too high to directly meet the application requirements.The toughness of the assembled membranes can be effectively improved by coassembled the rod-like biomass particle CNC with the flexible polymer.However,due to the low thermal processing temperature of CNC,the co-assembled membranes are still lack of processing ability,and further construction of achiral assembly structure with high luminescence quantum efficiency based on co-assembled is lack of effective control technology and theoretical support.Therefore,based on the low processing temperature characteristics of polycaprolactone(PCL),the co-assembly structure regulation technology of PCL composite membrane and rod-like biomass particles was studied,and the change rule and control mechanism of its luminescent characteristics were illustrated,and then the thermoplastic processing and patterning method of a colorful multi-level anti-counterfeiting membrane was constructed.Specific research contents and results are as follows:(1)In order to overcome the shortcomings of high brittleness and low toughness of the rod-like nanocrystalline membrane,and to ensure the transparency of the luminous membrane.In this study,rod-like nanocrystalline CNC was introduced into the polymer for co-assembled.Based on the two substrates of Tm 60℃ PCL and Tm 160℃polymethyl methacrylate(PMMA),the manufacturing process technology for realizing the transparency of co-assembled membrane was compared and explored.The results show that only by ensuring the feasibility of CNC assembly temperature,ultrasonic pretreatment,and other process technologies for the construction of co-assembly membranes,can the transparency be realized,and the photoluminescence be realized.Furthermore,PCL provides flexibility for co-assembled membrane,which solves the disadvantages of too high brittleness and insufficient workability of such materials.(2)In order to control the degree of chirality weakening of rod-like nanocrystalline arrays in the above co-assembled membranes,a new strategy of CNC achiral assembly was constructed in this study.Through the "two-step co-assembled",that is,pre-assembly and then co-assembled,the influence of assembly strategy on the assembly characteristics of CNC was studied,and the mechanism of controlling the luminescence characteristics of the co-assembled structure was further clarified,and the process optimization strategy of the co-assembled membrane optical sensor was studied.The results show that to eliminate the chirality of CNC in co-assembled membrane and ensure the feasibility of later processing,the two-step co-assembled method to construct pre-assembled array structure is an effective method to control the degree of chiral assembly of CNC in co-assembled membrane and maintain the luminescence performance.(3)Based on the patterning technology of co-assembled luminescent membranes and the thermoplastic processing ability of PCL,the optical information intensity and colorful patterning construction technology of rod-like nanocrystalline co-assembled materials were explored in this paper.Based on the size and refractive index differences between Ch NC and CNC,the achiral assembly monochromatic membranes with different luminescence wavelengths were constructed.Furthermore,combining with the flexible and thermoplastic processing characteristics of PCL,the colorful optical anti-counterfeiting membrane based on biomass rod-like nanocrystalline,and the patterned information coding technology were constructed.The results show that the luminescence intensity can be controlled quantitatively by hot-pressing machining.Further,the colorful was achieved through the composition of co-assembled membranes of different rod-like nanocrystals.In conclusion,this study solves the brittleness problem of rod-like nanocrystalline membrane by co-assembled rod-like biomass particles and flexible polymers and realizes the application of its achiral assembly materials in processing technology.Then the CNC was modified by surface modification to realize the achiral preassembly of CNC.Finally,through the control of structural color and the combination of different structural colors,the structural color patterns with different colors and different brightness are obtained,which gives the potential of the structural color materials in anti-counterfeiting. |
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