Emulsion Polymerization, Size Determination, and Self-Assembly of Monodispersed Poly(methyl methacrylate) Nanospheres for Photonics

Abstract

Polymers and nanochemistry are important facets of chemistry. In this experiment, students synthesize monodispersed poly­(methyl methacrylate) nanospheres from the addition or chain polymerization of a rapidly stirred aqueous mini-emulsion of methyl methacrylate. The 2,2′-azobis­(2-methylpropion­amidine) dihydrochloride serves as a heat activated, water-soluble, free radical initiator to polymerize the emulsion droplets starting from their outer edge. The uniform small diameter particles will appear iridescent if they are close-packed and their size is similar to the wavelength of visible light. Students characterize the size of the poly­(methyl methacrylate) spheres by four methods: the settling velocity and Stokes’ law, evaporative self-assembly of a photonic material and visible spectroscopy, direct measurement using scanning electron microscopy (SEM), and SEM measurement of the silica inverse opal. This experiment increases student collaboration and provides the opportunity to work on multiple experiments at once.

Photon Management Enabled by Opal and Inverse Opal Photonic Crystals: from Photocatalysis to Photoluminescence Regulation

“…Generally, colloidal particles for self‐assembly need to be sufficiently monodisperse, uniform in size and shape, and have sufficient surface charge so that they can form ordered assemblies to overcome premature particle aggregation due to universal attraction, i. e., van der Waals forces [71–74] . A range of colloidal particles with uniform sizes, such as SiO 2 , polystyrene (PS), polymethyl methacrylate (PMMA), and Fe 3 O 4 , can be readily fabricated on a large scale via solvent‐thermal methods, sol‐gel processes, emulsion polymerization, or acid hydrolysis [75–79] . With suitable colloidal particles, the ultimate goal of colloidal self‐assembly methods is to provide the driving force that prompts colloidal particles together in a uniformly organized manner to form high structural and optical quality colloidal crystals.…”

“…[71][72][73][74] A range of colloidal particles with uniform sizes, such as SiO 2 , polystyrene (PS), polymethyl methacrylate (PMMA), and Fe 3 O 4 , can be readily fabricated on a large scale via solvent-thermal methods, sol-gel processes, emulsion polymerization, or acid hydrolysis. [75][76][77][78][79] With suitable colloidal particles, the ultimate goal of colloidal self-assembly methods is to provide the driving force that prompts colloidal particles together in a uniformly organized manner to form high structural and optical quality colloidal crystals. Accordingly, colloidal self-assembly methods can be classified primarily based on the driving force, such as capillary forces or electrically and magnetically driven deposition methods.…”

Metal-Free Ring-Opening Polymerization of Propylene Oxide: Synthesis and Characterization of Polyether in the Undergraduate Organic Chemistry Laboratory

“…Over the past decade, publications on polymer topics in this Journal have been increasing to address the lack of polymer experiments in undergraduate teaching laboratories. Such developed experiments include extensive topics related to polymer science, − such as polycarbonates, polyamides, self-healing polymers, vitrimers, polystyrenes, polyesters, − poly( N -isopropylacrylamide), polyanilines, poly(methyl methacrylate), , and their synthesis, characterization, and applications.…”

Zooming in on Polymer Chemistry and Designing Synthesis of High Sulfur-Content Polymers for Virtual Undergraduate Laboratory Experiment

“…Designing laboratory experiments on polymers can connect students with real-world applications, spark and promote students’ interests in science, and help students visualize some fundamental concepts in chemistry. , Several in-person lab experiments on synthesis, characterization, analysis, and applications of polymers were previously covered in the Journal of Chemical Education − and recently (2017) published in the Journal of Chemical Education Special Issue on Polymer Concepts across the Curriculum . − Specifically, polymer syntheses using different polymerization techniques such as radical polymerization (e.g., free-radical, controlled/living: ATRP − and RAFT , ), ring-opening polymerization (ROP) ,− and ring-opening metathesis polymerization (ROMP), , and photopolymerization , were modified to design experiments for undergraduate (UG) laboratories; however, they were all designed for in-person experiments. Contrarily, many lab activities were envisioned, designed, and implemented for remote education even before pandemic time, − and several new studies have also been published in 2020, particularly in the Special Issue: Insights Gained While Teaching Chemistry in the Time of COVID-19 . − Despite the breadth of the literature on distance learning, new virtual laboratory experiments incorporating polymers are missing and can be beneficial.…”