In summary, the fundamentals of nanomaterials and its joining-related issues – from nanojoining by producing permanent unions or connection between the zero to two-dimensional nano-sized building blocks to the bulk joining assisted with nanomaterials for more desirable bonding condition and improved bonding properties – were reviewed. Nanojoining of nanomaterials in different components are introduced based on dimensional change, i.e., single-component (e.g., Ag, Pt) and multicomponent (e.g., CuO) nanoparticles, as well as one-dimensional nanowire and carbon nanotubes. Although nanojoining technology is very attractive, there are still limitations and a lot of works be done to develop the technology for real applications in industrial manufacturing process. Problems to be addressed include the limitation of machine operation and critical experimental conditions, low productivity, stability and reliability of samples, and so on. Some of them can be easily solved in the micro or even bigger range but will be tough in the nanorange. Compared to direct nanojoining of materials, nanomaterial-assisted joining appears to be more widely accepted and easily blended into existing markets and applications.
While it is exciting to notice the rapid growth in this area, one should also not neglect the evolving challenges in health and safety. Moving on, the involvement of all stakeholders (governments; international, regional, and national organizations; industry groups; public interest associations; labor organizations; scientific associations; and civil society) will be required to identify the impact of nanomaterials to health and safety in positive or negative ways and address policy issues accordingly. This will help in expediting more adoption of nanomaterials and nanotechnologies into our daily life.

References

Ajayan PM, Stephan O, Colliex C, Trauth D (1994) Aligned carbon nanotube arrays formed by cutting a polymer resin – nanotube composite. Science 265:1212–1214

Arai S, Fujimori A, Murai M, Endo M (2008) Excellent solid lubrication of electrodeposited nickel-multiwalled carbon nanotube composite films. Mater Lett 62:3545–3548

Bakshi SR, Singh V, Balani K, McCartney DG, Seal S, Agarwal A (2008) Carbon nanotube reinforced aluminum composite coating via cold spraying. Surf Coat Technol 202:5162–5169

Bakshi SR, Lahiri D, Agarwal A (2010) Carbon nanotube reinforced metal matrix composites – a review. Int Mater Rev 55:41–64

Bal S, Samal SS (2007) Carbon nanotube reinforced polymer composites – a state of the art. Bull Mater Sci 30:379–386

Balasubramanian K, Burghard M (2005) Chemically functionalized carbon nanotubes. Small 1:180–192

Banhart F (2001) The formation of a connection between carbon nanotubes in an electron beam. Nano Lett 1:329–332

Bao Z, Feng Y, Dodabalapur A, Raju VR, Lovinger AJ (1997) High-performance plastic transistors fabricated by printing techniques. Chem Mater 9:1299–1301

Buffat P, Borel JP (1976) Size effect on the melting temperature of gold particles. Phys Rev A 13:2287–2298

Cai H, Yan F, Xue Q (2004) Investigation of tribological properties of polyimide/carbon nanotube nanocomposites. Mater Sci Eng A 364:94–100

Chen WX, Tu JP, Wang LY, Gan HY, Xu ZD, Zhang XB (2003) Tribological application of carbon nanotubes in a metal-based composite coating and composites. Carbon 41:215–222

Cui Q, Gao F, Mukherjee S, Gu Z (2009) Joining and interconnect formation of nanowires and carbon nanotubes for nanoelectronics and nanosystems. Small 5:1246–1257

Deshpande VV, Chandra B, Caldwell R, Novikov DS, Hone J, Bockrath M (2009) Mott insulating state in ultraclean carbon nanotubes. Science 323:106

Dilandro L, Dibenedetto AT, Groeger J (1988) The effect of fiber-matrix stress transfer on the strength of fiber-reinforced composite materials. Polym Compos 9:209–221

Feng Y, Yuan HL, Zhang M (2005) Fabrication and properties of silver-matrix composites reinforced by carbon nanotubes. Mater Charact 55:211–218

Fuse T, Moriyama S, Aoyagi Y, Suzuki M, Ishibashi K (2003) Two-electron and four-electron periodicity in single-wall carbon nanotube quantum dots. Superlattices Microstruct 34:377

Garnier F, Hajlaoui R, Yassar A, Srivastava P (1994) All-polymer field-effect transistor realized by printing techniques. Science 265:1684–1686

Goh CS, Wei J, Lee LC, Gupta M (2008) Ductility improvement and fatigue studies in Mg-CNT nanocomposites. Compos Sci Technol 68:1432–1439

Gu Z, Chen Y, Gracias DH (2004) Surface tension driven self-assembly of bundles and networks of 200 nm diameter rods using a polymerizable adhesive. Langmuir 20:11308–11311

G€ulseren O, Ercolessi F, Tosatti E (1995) Premelting of thin wires. Phys Rev B 51:7377–7380 Guo C, Zuo Y, Zhao X, Zhao J, Xiong J (2007) The effects of pulse-reverse parameters on the properties of Ni-carbon nanotubes composite coatings. Surf Coat Technol 201:9491–9496

Hansen N (2004) Hall–Petch relation and boundary strengthening. Scr Mater 51:801 He C, Zhao N, Shi C, Du X, Li J, Li H, Cui Q (2007) An approach to obtaining homogeneously dispersed carbon nanotubes in Al powders for preparing reinforced Al-matrix composites. Adv Mater 19:1128–1132

Hensel JC, Tung RT, Poate JM, Unterwald FC (1985) Specular boundary scattering and electrical transport in single-crystal thin films of CoSi2. Phys Rev Lett 54:1840

Hiroshi N, Tomoaki H, Tadashi T (2011) Bonding process of Cu/Cu joint using Cu nanoparticle paste. Trans JWRI 40:33–36

Hongke Y, Zhiyong G, Yu T, Gracias DH (2006) Integrating nanowires with substrates using directed assembly and nanoscale soldering. Nanotechnol IEEE Trans 5:62–66

Hu A, Panda SK, Khan MI, Zhou Y (2009) Laser welding, microwelding, nanowelding and nanoprocessing. Chin J Lasers 36:3149–3159

Hu A, Guo JY, Alarifi H, Patane G, Zhou Y, Compagnini G, Xu CX (2010) Low temperature sintering of Ag nanoparticles for flexible electronics packaging. Appl Phys Lett 97:153117

Hulbert DM, Anders A, Andersson J, Lavernia EJ, Mukherjee AK (2009) A discussion on the absence of plasma in spark plasma sintering. Scr Mater 60:835–838

Ide E, Angata S, Hirose A, Kobayashi KF (2005) Metal-metal bonding process using Ag metalloorganic nanoparticles. Acta Mater 53:2385–2393

Kang X, Mai Z, Zou X, Cai P, Mo J (2007) A sensitive nonenzymatic glucose sensor in alkaline media with a copper nanocluster/multiwall carbon nanotube-modified glassy carbon electrode. Anal Biochem 363:143–150

Khang DY, Jiang H, Huang Y, Rogers JA (2006) A stretchable form of single-crystal silicon for high-performance electronics on rubber substrates. Science 311:208

Kiefer AM, Paskiewicz DM, Clausen AM, Buchwald WR, Soref RA, Lagally MG (2011) Si/Ge junctions formed by nanomembrane bonding. ACS Nano 5:1179

Kittel C (2005) Introduction to solid state physics. Wiley, New York

Ko SH, Park I, Pan H, Grigoropoulos CP, Pisano AP, Luscombe CK, Fre´chet JMJ (2007a) Direct nanoimprinting of metal nanoparticles for nanoscale electronics fabrication. Nano Lett 7:1869–1877

Ko SH, Pan H, Grigoropoulos CP, Luscombe CK, Fre´chet JMJ, Poulikakos D (2007b) All-inkjet printed flexible electronics fabrication on a polymer substrate by low-temperature high-resolution selective laser sintering of metal nanoparticles. Nanotechnology 18:345202

Kuzmany H, Kukovecz A, Simon F, Holzweber M, Kramberger C, Pichler T (2004) Functionalization of carbon nanotubes. Synth Met 14:113–122

Laha T, Agarwal A, McKechnie T, Seal S (2004) Synthesis and characterization of plasma spray formed carbon nanotube reinforced aluminum composite. Mater Sci Eng A 381:249–258

Li L, Hu J, Yang W, Alivisatos AP (2001) Band gap variation of size- and shape-controlled colloidal CdSe quantum rods. Nano Lett 1:349

Lourie O, Wagner HD (1998) Transmission electron microscopy observations of fracture of single-wall carbon nanotubes under axial tension. Appl Phys Lett 73:3527

Lu Y, Huang JY, Wang C, Sun S, Lou J (2010) Cold welding of ultrathin gold nanowires. Nat Nanotechnol 5:218–224

Mafune´ F, Kohno J-Y, Takeda Y, Kondow T (2003) Nanoscale soldering of metal nanoparticles for construction of higher-order structures. J Am Chem Soc 125:1686–1687

McEuen P (2005). Introduction to solid state physics (ed: Johnson S). Wiley, New Jersey, pp 515–564

Mehrotra G, Jha G, Goud JD, Raj PM, Venkatesan M, Iyer M, Hess D, Tummala R (2008). Low-temperature, fine-pitch interconnections using self-patternable metallic nanoparticles as the bonding layer. In: Electronic components and technology conference, pp 1410–1416

Nai SML, Wei J, Gupta M (2006) Improving the performance of lead-free solder reinforced with multi-walled carbon nanotubes. Mater Sci Eng A 423:166–169

Pande CS, Masumura RA, Armstrong RW (1993) Pile-up based Hall–Petch relation for nanoscale materials. Nanostruct Mater 2:323

Qi X, Xue C, Huang X, Huang Y, Zhou X, Li H, Liu D, Boey F, Yan Q, Huang W, De Feyter S, M€ullen K, Zhang H (2009) Polyphenylene dendrimer-templated in situ construction of inorganic–organic hybrid rice-shaped architectures. Adv Funct Mater 20:43–49

Qi X, Huang Y, Klapper M, Boey F, Huang W, Feyter SD, M€ullen K, Zhang H (2010) In situ modification of three-dimensional polyphenylene dendrimer-templated CuO rice-shaped architectures with electron beam irradiation. J Phys Chem C 114:13465–13470

Ridley BA, Nivi B, Jacobson JM (1999) All-inorganic field effect transistors fabricated by printing. Science 286:746–749

Rogers JA, Lagally MG, Nuzzo RG (2011) Synthesis, assembly and applications of semiconductor nanomembranes. Nature 477:45

Seo M-K, Park S-J (2004) Electrical resistivity and rheological behaviors of carbon nanotubesfilled polypropylene composites. Chem Phys Lett 395:44–48

Shi WS, Zheng YF, Wang N, Lee CS, Lee ST (2001) A general synthetic route to III–V compound semiconductor nanowires. Adv Mater 13:591–594

Sinian L, Souzhi S, Tianqin Y, Huimin C, Youshou Z, Hong C (2005) Microstructure and fracture surfaces carbon nanotubes/magnesium matrix composite. Mater Sci Forum 488/489:893–896

Siochi EJ, Working DC, Park C, Lillehei PT, Rouse JH, Topping CC, Bhattacharyya AR, Kumar S (2004) Melt processing of SWCNT-polyimide nanocomposite fibers. Compos Part B Eng 35:439–446

Sirringhaus H, Kawase T, Friend RH, Shimoda T, Inbasekaran M, Wu W, Woo EP (2000) Highresolution inkjet printing of all-polymer transistor circuits. Science 290:2123–2126

Song YS, Youn JR (2005) Influence of dispersion states of carbon nanotubes on physical properties of epoxy nanocomposites. Carbon 43:1378–1385

Stutzmann N, Friend RH, Sirringhaus H (2003) Self-aligned, vertical-channel, polymer field-effect transistors. Science 299:1881–1884

Tang J, Wang H-T, Lee DH, Fardy M, Huo Z, Russell TP, Yang P (2010) Holey silicon as an efficient thermoelectric material. Nano Lett 10:4279

Terrones M, Banhart F, Grobert N, Charlier JC, Terrones H, Ajayan PM (2002) Molecular junctions by joining single-walled carbon nanotubes. Phys Rev Lett 89:075505

Tohmyoh H, Fukui S (2009) Self-completed Joule heat welding of ultrathin Pt wires. Phys Rev B 80:155403

Tohmyoh H, Imaizumi T, Hayashi H, Saka M (2007) Welding of Pt nanowires by Joule heating. Scr Mater 57:953–956

Wakuda D, Hatamura M, Suganuma K (2007) Novel method for room temperature sintering of Ag nanoparticle paste in air. Chem Phys Lett 441:305

Wakuda D, Kim K-S, Suganuma K (2010) Ag nanoparticle paste synthesis for room temperature bonding. IEEE Trans Compon Packag Technol 33:437–442

Wang Y, Herron N (1991) Nanometer-sized semiconductor clusters: materials synthesis, quantum size effects, and photophysical properties. J Phys Chem 95:525

Wang JZ, Zheng ZH, Li HW, Huck WTS, Sirringhaus H (2004) Dewetting of conducting polymer inkjet droplets on patterned surfaces. Nat Mater 3:171–176

Xu CL, Wei BQ, Ma RZ, Liang J, Ma XK, Wu DH (1999) Fabrication of aluminum-carbon nanotube composites and their electrical properties. Carbon 37:855–858

Yang K, Gu M, Guo Y, Pan X, Mu G (2009) Effects of carbon nanotube functionalization on the mechanical and thermal properties of epoxy composites. Carbon 47:1723–1737

Yu J-K, Mitrovic S, Tham D, Varghese J, Heath JR (2010) Reduction of thermal conductivity in phononic nanomesh structures. Nat Nanotechnol 5:718

Zhan J, Bando Y, Hu J, Liu Z, Yin L, Golberg D (2005) Fabrication of metal–semiconductor nanowire heterojunctions. Angew Chem Int Ed 44:2140–2144

Zhang H, Grim PCM, Vosch T, Wiesler UM, Berresheim AJ, M€ullen K, De Schryver FC (2000) Discrimination of dendrimer aggregates on mica based on adhesion force: a pulsed force mode atomic force microscopy study. Langmuir 16:9294–9298

Zhang W, Brongersma SH, Richard O, Brijs B, Palmans R, Froyen L, Maex K (2004) Influence of the electron mean free path on the resistivity of thin metal films. Microelectron Eng 76:146

Zhao M, Li JC, Jiang Q (2003) Hall–Petch relationship in nanometer size range. J Alloys Compd 361:160