从蘸笔纳米刻印术到力化学打印

Evolution from dip-pen nanolithography to mechanochemical printing

蘸笔纳米刻印术(dip-pen nanolithography,DPN)作为一种独特的纳米加工手段,具有在各类基底上书写精细图案的能力.自20世纪末诞生以来,研究者们对DPN中的墨水输运原理有了更深入的理解,同时受惠于材料学的发展并结合复杂生化反应体系,数种基于DPN衍生的纳米加工技术被开发出来.与此同时,依靠机械作用引发的一类化学反应,即力化学(mechanochemistry),在最近数十年来获得了越来越多的关注,多种新颖的实验方法被引入.本综述将介绍DPN及若干衍生技术的原理与应用,以及力化学的机理与实现方法,进而探讨结合这两者优势发展力化学打印的可能,并揭示其在纳米技术及原子制造领域的应用前景.

As a unique nanomanipulation and nanofabrication tool,dip-pen nanolithography(DPN)has enjoyed great success in the past two decades.The DPN can be used to create molecular patterns with nanoscale precision on a variety of substrates with different chemistry properties.Since its advent,the DPN has been steadily improved in the sense of applicable inks,fabrication throughput,and new printing chemistry.Among these developments,mechanical force induced mechanochemistry is of special interest.In this review,we introduce the physical principles behind the DPN technique.We highlight the development of DPN for writing with various types of"inks",including small molecules,viscous polymer solutions,lipids,and biomolecules,especially,the development of thermal-DPN allowing printing with inks that are usually in solid phase at room temperature.Next,we introduce the parallel-DPN and polymer pen nanolithography.These techniques greatly speed up the fabrication speed without sacrificing the precision.We also summarize the advances in chemical reaction based DPN technologies,including electrochemical DPN,metal tip-induced catalytical DPN,and mechanochemical DPN(or mechanochemical printing).To further elaborate the mechanism behind the mechanochemical printing,we briefly review the development of mechanochemistry,including the reaction mechanism,various experimental approaches to realizing mechanochemistry,and recent development in this field.We highlight the advantages of using atomic force microscopy to study mechanochemistry at a single molecule level and indicate the potential of combining this technique with DPN to realize mechanochemical printing.We envision that with the further discovery of novel mechanophores that are suitable for mechanochemical printing,this technique can be broadly applied to nanotechnology and atomic fabrication.