Deaggregation And Chemical Modification Of Nanodiamond

Nanodiamond?ND?endowed with excellent properties both of large diamond and nanometer materials has got wide attention and research since its discovery in 1960s.And with its preparation technology matures and the rapid development of nanotechnology,the applications of nanodiamond is also becoming increasingly widespread,especially in the field of life science.Nanodiamond shows great application potentiality and has caused wide public concern depend on its excellent properties,such as good biocompatibility,non-toxicity,fluorescent and antiseptic properties,etc.However,it's hard for nanodiamond to exist stably in nanoscale particles form because of its high specific surface area and unique structure of nanometer?rich in hydrogen bonds,surface hydroxyl,ester,carbonyl and other functional groups?.Nanodiamond particles have a strong tendency to aggregate and usually exist in the form of micro-sized aggregates.Nanodiamond can't exhibit or even lose its outstanding properties,which limits its further application in many areas.Thus,it is of great importance to find out an efficient way to improve the dispersion of nanodiamond particles which can give full use of its excellent propertites as nanoparticle and provide further applications.In this study,we put our attention on the chemical dispersion of nanodiamonds.Two macromolecular material poly??-caprolactone?and polyphosphazene,both of excellent biocompatibility and environmentally friendly,were used to make functionalization of nanodiamond in chemical method.?1?Functionalization of nanodiamond with biodegradable poly??-caprolactone?Two approaches were developed to graft biodegradable poly??-caprolactone?from ND surface to achieve the functionalization of agglomerating NDs.ND particles were first added into a solution of strong oxidizing acid to gain carboxylic ND?ND-COOH?.Next,ND-COOH were treatment with hexamethylene diisocyanate?or thionyl chlorides?and glucose successively which gained two kinds ND-OH.Then,ring-opening polymerization of?-caprolactone proceeded by initiation of the two hydroxyl group-functionalized ND and tin?II?2-ethylhexanoate.We realized the dispersion and deaggregation of NDs by grafting biodegradable poly??-caprolactone?from ND surface.The dispersion and hydrophobicity of NDs has been significantly improved after modification with poly??-caprolactone?.The NDs modified by poly??-caprolactone?provide a new method to functionalize and deaggregate ND particles,and thus a new prospect of multipurpose applications both in biomedical systems and in other fields.?2?Functionalization of nanodiamond with biodegradable polyphosphazeneND particles were first added into a solution of strong oxidizing acid.The generated carboxyl groups were next converted into amino groups by treatment with ethylenediamine?ND-NH₂?.At the same time,polyphosphazene was manufactured by phosphonitrilic chloride trimer via ring-opening polymerization.Then,the functionalized ND particles were grafted with biological non-toxic polyphosphazene via"grafting to"method.The dispersion of polyphosphazene-grafted NDs has improved to a certain extent,and it presents a new approach and direction for the functionalization of ND.