The Fabrication Of Monodispersed Mesoporous Carbon Nanospheres And Their Adsorption/Release Studies

Uniform,monodispersed mesoporous carbon nanospheres?UM-MCNs?have stable mesoscopic structure,flexibly adjustable pore structure and morphology,ultra-high pore volume,high specific surface area,and excellent biological properties,which have been widely used in electrochemistry,biomedicine,catalytic separation,pollutant adsorption and so on.Especially as a drug carrier,UM-MCNs have the potential to quantificationally encapsulate drugs and to be easily recognized/adsorbed by cells.However,there are still some problems that need to be solved to obtain UM-MCNs with excellent performance:?1?hard templating method has been used to obtain UM-MCNs,which always needed multi-steps with high cost;?2?high-temperature carbonization caused phenolic resins to adhere to each other,shrink and even collapse;?3?the balance of precursor polymerization rate and self-assembly rate in the organic-organic self-assembly method was difficult to control;?4?multifunctional mesoporous composite nanoparticles have been urgently needed in practical applications,single-structured mesoporous carbon nanospheres?MCNs?cannot meet various application requirements,but mesoporous composite nanoparticles were difficult to obtain due to the complex structure.These problems have greatly limited the application and large-scale production of mesoporous nanoparticles.Therefore,the preparation of monodisperse,large mesopores,small-sized carbon nanospheres and complex mesoporous composite nanoparticles still remains significant challenge.The main research methods of this paper are:1)we innovatively simplified the synthesis method and expanded the organic-organic self-assembly mechanism;2)the uniformity,dispersion,morphology,pore size and stability of MCNs were controlled by regulating variables;3)the synthesis method and formation mechanism were explored for UM-MCNs and mesoporous carbon/silicon composite particles;4)the mesoporous carbon materials were explored to apply in the fields of drug carriers and water treatment.The purpose was to solve the problems we faced in the synthesis of mesoporous nanoparticles with good performance,thus to improve drug loading/release and adsorption performance.The BCS?drugs?albendazole,naproxen?were selected to investigate the adsorption/release properties of MCNs and the dye?neutral red?was used to investigate the adsorption properties of the composite nanoparticles.This paper mainly includes the following aspects and conclusions:1.The hydrogen bonding interaction between the hydrophilic chains of the soft template and the carbon precursor will definitely affect the morphology and structure of the mesoporous carbon material.However,the effect of the hydrophilic chains on organic-organic self-assembly hasn't been reported,so it is necessary to deeply elaborate on the organic-organic self-assembly mechanism.In this paper,it was discovered for the first time that F108 with long hydrophilic chains not only acted as the porogen,but also as the rate regulator and structural stabilizer,which was beneficial for the formation of UM-MCNs with small particle size,large mesopores and excellent thermal stability.The influence on the shape and pore structure of MCNs were further explored by adjusting the amount of F108 and the initial temperature,which have enriched the mechanism of organic-organic self-assembly.In addition,the dissolution experiment was conducted to verify the the excellent drug adsorption/release properties of MCNs and the cytotoxicity experiment was carried out to verify the good bio-compatibility of MCNs.2.The mechanism of ethanol in the organic-organic self-assembly process was proposed systematically for the first time,and it found that ethanol could be used as a co-surfactant or a co-solvent.When the volume ratio of ethanol/H₂O in the system was small,ethanol as a co-surfactant was only embedded in the triblock copolymer,which interfered with the organic-organic self-assembly process,and finally changed the pore structure and morphology of the MCNs;When the volume ratio of ethanol/H₂O in the system was large,ethanol as a latent solvent was mixed with the water in the system,which inhibited the organic-organic self-assembly process and made the nucleation process slow,thus the obtained MCNs became larger in particle size and smaller in pore size.Naproxen with poor water-solubility was used as model drug to investigate the adsorption/release properties of nanospheres with different specific surface areas,different pore volumes,and different pore sizes.3.With the classic nucleation theory,heterogeneous nucleation has lower energy barrier than homogeneous nucleation.For the first time,by using the polymer nanoparticles with highly uniformity,dispersion,small particle size and good thermal stability as basic core,hydrogen peroxide as sample activator,TEOS as heterogeneous silicon source,CTAB as structure directing agent,triethanolamine and ammonia as catalysts,C@mSi O₂ composite nanoparticles with highly dispersion,stable structure and janus structure were obtained.Compared to previous methods,the synthesis step was simplified.The mechanism of Ammonia as catalyst and intermediate medium was clarified,which provided a theoretical basis for the customization of specific composite particles.The mechanism of CTAB to affect the internal structure of composite particles was clarified.Moreover,neutral red was chosen as a model molecule to verify the excellent adsorption performance of C@mSiO₂ composite nanoparticles.