**4. Conclusion and outlook**

Many hypotheses posed by researchers across the world would be answered by observing reactions in real time. To achieve this, two major technologies provide significant opportunity when merged: SAXS and optimised microfluidic setups. Although the last decades of research lead to significant developments in combining these fields, it remains a demanding intersection of methods with the potential to answer many fundamental questions around nucleation, growth and self-assembly of materials on the nanoscale. New three-dimensional hydrodynamic focusing device designs show great promise in studying a variety of systems – from organic to inorganic and crystal growth to self-assembly processes. Nevertheless, this is still an emerging field, with microfluidic and synchrotron technologies continuing to push the boundaries of possible experiments, opening up new possibilities for further reducing dead times, and thereby understanding the earliest parts of synthesis reactions, which are of critical importance in future control and modification of nanoparticles for a wide variety of purposes. Micro-focused X-ray beams and beamline optimisation, meanwhile, will be a key component to access faster timescales with SAXS. We hope that this overview of microfluidics and SAXS analyses, along with some of our insights will aid future investigations into this challenging, but exciting field.

**References**

1046–8.

261:895–7.

67:3676–80.

1992;593:253–8.

303.

**29**

977–1026.

[1] Manz A, Graber N, Widmer HM. Miniaturized total chemical analysis systems: A novel concept for chemical sensing. Sensors and Actuators B:

*DOI: http://dx.doi.org/10.5772/intechopen.95059*

*Microfluidics for Time-Resolved Small-Angle X-Ray Scattering*

[10] Lee CY, Chang CL, Wang YN, Fu LM. Microfluidic mixing: a review.

Int J Mol Sci. 2011;12:3263–87.

[11] Ward K, Fan ZH. Mixing in microfluidic devices and enhancement methods. J Micromech Microeng.

[12] Capretto LC, W; Hill, M; Zhang,X. Micromixing Within Microfluidic Devices. Microfluidics. Berlin, Heidelberg: Springer; 2011. p. 27–68.

[13] Feigin LA, Svergun DI, Taylor GW. Structure Analysis by Small-Angle X-Ray and Neutron Scattering. Boston,

[14] Bruus H. Theoretical microfluidics. Oxford: Oxford University Press; 2008.

[15] Lu M, Ozcelik A, Grigsby CL, Zhao Y, Guo F, Leong KW, et al. Microfluidic Hydrodynamic Focusing for Synthesis of Nanomaterials. Nano

MA: Springer US; 1987.

Today. 2016;11:778–92.

2000;21:27–40.

1998;70:4974–84.

550–75.

[16] McDonald JC, Duffy DC, Anderson JR, Chiu DT, Wu H, Schueller OJA, et al. Fabrication of microfluidic systems in poly

[17] Duffy DC, McDonald JC, Schueller OJ, Whitesides GM. Rapid Prototyping of Microfluidic Systems in Poly(dimethylsiloxane). Anal Chem.

[18] Xia Y, Whitesides GM. Soft Lithography. Angewandte

Technologies. 1998;4:122–4.

Chemie International Edition. 1998;37:

[19] Heckele M, Bacher W, Müller KD. Hot embossing - The molding technique for plastic microstructures. Microsystem

(dimethylsiloxane). Electrophoresis.

2015;25.

Chemical. 1990;1:244–8.

Effenhauser CS, Manz A. Micromachining a miniaturized

Anal Chem. 1997;69:3407–12.

[6] Manz A, Harrison DJ,

[7] Ingham B. X-ray scattering characterisation of nanoparticles. Crystallography Reviews. 2015;21:229–

[2] Kopp MU, Mello AJ, Manz A. Chemical amplification: continuousflow PCR on a chip. Science. 1998;280:

[3] Harrison DJ, Fluri K, Seiler K, Fan Z,

capillary electrophoresis-based chemical analysis system on a chip. Science. 1993;

[4] Hadd AG, Raymond DE, Halliwell JW, Jacobson SC, Ramsey JM. Microchip device for performing enzyme assays.

[5] Woolley AT, Mathies RA. Ultra-highspeed DNA sequencing using capillary electrophoresis chips. Anal Chem. 1995;

Verpoorte EMJ, Fettinger JC, Paulus A, Lüdi H, et al. Planar chips technology for miniaturization and integration of separation techniques into monitoring systems. Journal of Chromatography A.

[8] Squires TM, Quake SR. Microfluidics: Fluid physics at the nanoliter scale. Reviews of Modern Physics. 2005;77:

[9] Neto C, Evans DR, Bonaccurso E, Butt H-J, Craig VSJ. Boundary slip in Newtonian liquids: a review of experimental studies. Reports on Progress in Physics. 2005;68:2859–97.
