Walden Sarah L, Hooker Jordan P, Delafresnaye Laura, Barner-Kowollik Christopher
School of Chemistry and Physics, Queensland University of Technology (QUT), 2 George Street, Brisbane, QLD 4000, Australia.
Centre for Materials Science, Queensland University of Technology (QUT), 2 George Street, Brisbane, QLD 4000, Australia.
ACS Macro Lett. 2021 Jul 20;10(7):851-856. doi: 10.1021/acsmacrolett.1c00319. Epub 2021 Jun 23.
Herein, we establish the effect of intensity and wavelength on the size of microparticles formed via precipitation polymerization, employing photocrosslinkable prepolymers. Simultaneous measurement of backscattered laser irradiation enabled real-time tracking of particle growth and provides the ability to vary the LED intensity (λ = 415 nm) during various stages of particle growth. Critically, particle diameters can be controlled between 200 and 700 nm by varying the LED power from 73 to 0.63 mW, respectively. High intensities during the nucleation phase-spanning only the initial seconds-were found to dictate the particle diameter, irrespective of the energy used during the growth phase. Finally, a bathochromic shift was observed between the wavelength generating the highest rate of particle formation and the absorbance maxima of the photoactive group. We submit that these findings are broadly applicable in the continuously developing field of photoinitiated synthesis of polymer particles.
在此，我们利用可光交联预聚物，研究了强度和波长对通过沉淀聚合形成的微粒尺寸的影响。对背散射激光照射的同步测量能够实时跟踪颗粒生长，并能够在颗粒生长的各个阶段改变LED强度（λ = 415 nm）。至关重要的是，通过分别将LED功率从73 mW变化到0.63 mW，可以将颗粒直径控制在200至700 nm之间。发现在仅持续最初几秒的成核阶段的高强度决定了颗粒直径，而与生长阶段所使用的能量无关。最后，在产生最高颗粒形成速率的波长与光活性基团的吸收最大值之间观察到红移。我们认为这些发现广泛适用于不断发展的聚合物颗粒光引发合成领域。
