Interfacial Interaction Of Confined Polymers Studied By FRET

Fluorescence nonradiative Energy Transfer(FRET)is the method to study the conformation of the polymer chain and through to each other by grafting fluorescence donor and receptor to polymers and generating energy transfer within a certain range.Due to the sensitive distance between receptor and donor,FRET method for the molecular structure and molecular interaction provides a direct,simple and sensitive way.This paper developed a new interface characterization method,and studied structure and dynamics of the molecular chain of polymer chain confined in two-dimensional nanopores by method of grafting the fluorescent groups to the polymer chains and substrate respectively through FRET.In this interface fluorescence method,we will graft fluorescent receptors to AAO and graft fluorescence donor to the chain,pure the polymer into the pores fo AAO and measure the distance between the polymer and the interface according to the peak intensity ratios at under different cooling rates.Experiments show that when the rapid cooling(cooling rate up to 120 K/s),the distance between the polymer and two-dimensional nanopores interface is more bigger than slow cooling(cooling rate up to 0.5 K/s).At the same time complementary with DSC test in glass transition temperature under different cooling rates,there are two tgs when the cooling rate at 0.5 K/s,but there is one tg at when the cooling rate at 120 K/s,which is the same with bulk.DSC results show that,than interactions between the polymer and the hole wall when cooling at a slower rate is more stronger than the interaction when cooling at a fast rate.The stronger interaction makes the interface layer between polymer and hole wall and leads to the generation of high Tg.And from that on the other hand,polymer pill off from hole wall,and the distance is greater than the distance during slow cooling when cooling at a rapid rate.In order to understand more about the conformation of confined polymers,we design and systhesize different kinds of polymers with fluorescence chormophores.Grafting fluorescence chormophores to polymer chains can be devided into two parts.One belongs to the ends of the chain,the other one belongs to graft randomoly to the chain.For the ends of the chain,we graft the fluorescent chormophores to the polyer molecular chain by atom transfer radical polymerization(ATRP)and Click Chemistry.At first,fluorescence acceptors will be grafted onto the initiator,then we get the polymer of target molecular with fluorescence acceptors by atom transfer radical polymerization.At last,the fluorescence donor grafted to the polymer chain on the other side by click reaction,then the target product is prepared.For polymers with fluorescent chormophores randomly,we usually adopt the method of modification to prepare.