Name: self-assembling morphologies obtained from helical polycarbodiimide copolymers and their triazole derivatives
Uploaded: 2017-02-07T13:00:00
Description: Watch this Scientific Journal Video about Self-assembling Morphologies Obtained from Helical Polycarbodiimide Copolymers and Their Triazole Derivatives at JoVE.com

We gratefully acknowledge the NSF-MRI grant (CHE-1126177) used to purchase the Bruker Advance III 500 NMR instrument.

NOTE: All reactions were performed in a glove box (or fume hood, when noted) using standard scintillation vials.
1. Synthesis of the (R)- and (S)-series of Ethynylpolycarbodiimides
<ol>
	<li>Place 1.0 g (0.00442 mol) of N-(3-ethynylphenyl)-N&#39;-hexylcarbodiimide monomer (ET) and 0.894 g (0.00442 mol) of N-phenyl-N&#39;-hexylcarbodiimide monomer (Ph) as transparent, viscous liquids in a clean scintillation vial (20 mL) with ...

<ol>
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M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Advances+in+polycarbodiimide+chemistry.">Advances in polycarbodiimide chemistry.</a> Polymer. 52, 1693-1710 (2011).</li><li>Arnold, L., Marx, A., Thiele, C. M., Reggelin, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Polyguanidines+as+Chiral+Orienting+Media+for+Organic+Compounds.">Polyguanidines as Chiral Orienting Media for Organic Compounds.</a> Chem. Eur. J. 16, 10342-10346 (2010).</li><li>Kennemur, J. G., Clark, J. B., Tian, G., Novak, B. 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In summary, the spin-coating deposition method represents a convenient way to reproducibly generate multiple-type morphologies, including fiber-like aggregates, ribbons, worm-like structures, fibrillar networks, looped fibers, toroids, and superhelices, from either alkyne polycarbodiimides or from their respective PS-derivatives (i.e., polycarbodiimide-g-polystyrenes). Thus, coordination-insertion polymerization, along with further functionalization using a &#34;click&#34; reaction followed by ATRP, pro...

The helix is a ubiquitous chiral motif observed in nature. Complex biological systems and their components, such as proteins, polypeptides, and DNA, all utilize the helical structure as a means of performing complex tasks for applications like information storage, tissue molecular transportation support, and localized chemical transformations.
Helical polymeric macromolecules1 have been a target for the design of functional materials and composites possessing interesting properties, which enabled their practical use in many areas2,3,4,5. So far, numerous helical scaffolds6,7,8,9, as well as their secondary structure motifs, have been successfully exploited to achieve promising results, both in the field of physical engineering10,11,12 and in biological applications13,14. Current studies represent a logical extension of our earlier efforts to synthesize optically active alkyne polycarbodiimides bearing one or two modifiable alkyne moieties per repeat unit15,16,17.
Recently, we reported22 the homo- and co-polymerization of carbodiimide monomers leading to chiral helical macromolecules &#8212; a family of (R)- and (S)-polycarbodiimides with modifiable pendant groups that offer further functionalization through a CuAAC &#34;click&#34; protocol. Br-terminated polycarbodiimides obtained from their respective ethynyl precursors were shown to act as ATRP macroinitiators in graft-polymerization with styrene23.
The specific aim of this manuscript is to provide a practical guide for morphological characterizations (AFM measurements and SEM inspection) of the secondary structures formed from PS-PCDs synthesized from their corresponding ethynyl precursors by using a well-known click protocol21. In particular, experimental details, such as the solvent of choice, the temperature, the deposition method, the substrate chosen for deposition, and the polymer structure, were shown to be highly important to obtain specific morphologies (e.g., fibers, including right- and left-handed helical senses; nano-spheres; and nano-rings). They may also be of use for the development of materials with tunable properties based on polycarbodiimides with precisely controlled chiral architecture.

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		<tr height="42">
			<td height="42" style="height:42px;width:216px;">styrene</td>
			<td style="width:71px;">Sigma-Aldrich</td>
			<td style="width:119px;">S4972-1L</td>
			<td style="width:167px;">reagent</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">N,N,N&#8242;,N&#8242;&#8242;,N&#8242;&#8242;- Pentamethyldiethylenetriamine (PMDETA)</td>
			<td style="width:71px;">Sigma-Aldrich</td>
			<td>369497-250ML</td>
			<td>reagent</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Copper(I) iodide</td>
			<td style="width:71px;">Sigma-Aldrich</td>
			<td style="width:119px;">215554-5G</td>
			<td>reagent</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Copper(I) chloride</td>
			<td style="width:71px;">Alfa-Aesar</td>
			<td style="width:119px;">14644, 5G</td>
			<td>reagent</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU)</td>
			<td style="width:71px;">Sigma-Aldrich</td>
			<td style="width:119px;">139009-100G</td>
			<td>reagent</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">N,N-dimethylformamide (DMF)</td>
			<td style="width:71px;">Sigma-Aldrich</td>
			<td style="width:119px;">227056-100mL</td>
			<td>solvent</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Tetrahydrofuran (THF)</td>
			<td style="width:71px;">Acros-Organics</td>
			<td style="width:119px;">B0320346</td>
			<td>solvent</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Chloroform</td>
			<td style="width:71px;">Sigma-Aldrich</td>
			<td style="width:119px;">372978-100mL</td>
			<td>solvent</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Methanol</td>
			<td style="width:71px;">Fisher-Chemical</td>
			<td style="width:119px;">A411-20</td>
			<td>solvent</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">20 mL glass scintillation vials</td>
			<td style="width:71px;">Cole-Palmer</td>
			<td style="width:119px;">UX-08918-03</td>
			<td>glassware</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">1-Dram vials (15 x 45 mm)</td>
			<td style="width:71px;">Kimble-Chase</td>
			<td style="width:119px;">KIM-60965D-1</td>
			<td>glassware</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">13 mm syringe filter with 0.45&#181;m PTFE membrane</td>
			<td style="width:71px;">VWR International</td>
			<td style="width:119px;">28145-493</td>
			<td>membrane filter</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">Silicon wafer disks (25.4&#177; .5 mm)</td>
			<td style="width:71px;">Wafer World, Inc</td>
			<td style="width:119px;">S076453</td>
			<td>AFM substrate</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Corning Stirrer/Hot Plate</td>
			<td style="width:71px;">Hot Plate</td>
			<td style="width:119px;">PC-420</td>
			<td>heating device</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">single stage Unilab mBraun glove box</td>
			<td style="width:71px;">Unilab</td>
			<td style="width:119px;">12-109</td>
			<td>glove box</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">Nanoscope IV-Multimode Veeco AFM-machine</td>
			<td style="width:71px;">Veeco</td>
			<td style="width:119px;">3100 Dimension V Atomic Probe Microscope</td>
			<td>AFM-instrument</td>
		</tr>
	</tbody>
</table>

self-assembling morphologies obtained from helical polycarbodiimide copolymers and their triazole derivatives

A facile method for the preparation of polycarbodiimide-based secondary structures (e.g., nano-rings, &#34;craters,&#34; fibers, looped fibers, fibrous networks, ribbons, worm-like aggregates, toroidal structures, and spherical particles) is described. These aggregates are morphologically influenced by extensive hydrophobic side chain-side chain interactions of the singular polycarbodiimide strands, as inferred by atomic force microscopy (AFM) and scanning electron microscopy (SEM) techniques. Polycarbodiimide-g-polystyrene copolymers (PS-PCDs) were prepared by a combination of synthetic methods, including coordination-insertion polymerization, copper(I)-catalyzed azide alkyne cycloaddition (CuAAC) &#34;click&#34; chemistry, and atom transfer radical polymerization (ATRP). PS-PCDs were found to form specific toroidal architectures at low concentrations in CHCl3. To determine the influence of a more polar solvent medium (i.e., THF and THF/EtOH) on polymer aggregation behavior, a number of representative PS-PCD composites have been tested to show discrete concentration-dependent spherical particles. These fundamental studies are of practical interest to the development of experimental procedures for desirable architectures by directed self-assembly in thin film. These architectures may be exploited as drug carriers, whereas other morphological findings represent certain interest in the area of novel functional materials.

Figure 1 (upper panel) illustrates BINOL (R)- or (S)-titanium (IV) catalyst-mediated coordination-insertion polymerization leading to the (R)- and (S)-series of ethynylpolycarbodiimides with an altering ratio of the repeat units (i.e., aryl- and alkyne aryl). Monomers and catalysts were obtained as described elsewhere18. Both (R)- and (S)-family alkyne random copolymers were selected fo...

Watch this Scientific Journal Video about Self-assembling Morphologies Obtained from Helical Polycarbodiimide Copolymers and Their Triazole Derivatives at JoVE.com

Self-assembling Morphologies Obtained from Helical Polycarbodiimide Copolymers and Their Triazole Derivatives

Here, we present a protocol to prepare and visualize secondary structures (e.g., fibers, toroidal architectures, and nano-spheres) derived from helical polycarbodiimides. The morphology characterized by both atomic force microscopy (AFM) and scanning electron microscopy (SEM) was shown to depend on molecular structure, concentration, and the solvent of choice.

A facile method for the preparation of polycarbodiimide-based secondary structures (e.g., nano-rings, &#34;craters,&#34; fibers, looped fibers, fibrous ...

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Molecules bearing trifluoromethoxy (OCF3) group often show desired pharmacological and biological properties. However, facile synthesis of ...

Functionalization of Single-walled Carbon Nanotubes with Thermo-reversible Block Copolymers and Characterization by Small-angle Neutron Scattering

We demonstrate a protocol for single-walled carbon nanotube functionalization using thermo-sensitive PEO-PPO-PEO triblock copolymers in an aqueous ...

Combustion Chemistry of Fuels: Quantitative Speciation Data Obtained from an Atmospheric High-temperature Flow Reactor with Coupled Molecular-beam Mass Spectrometer

This manuscript describes a high-temperature flow reactor experiment coupled to the powerful molecular beam mass spectrometry (MBMS) technique. This ...

Constructing Thioether/Vinyl Sulfide-tethered Helical Peptides Via Photo-induced Thiol-ene/yne Hydrothiolation

Here, we describe a detailed protocol for the preparation of thioether-tethered peptides using on-resin intramolecular/intermolecular thiol-ene ...

Facile Protocol for the Synthesis of Self-assembling Polyamine-based Peptide Amphiphiles (PPAs) and Related Biomaterials

Facile Protocol for the Synthesis of Self-assembling Polyamine-based Peptide Amphiphiles PPAs and Related Biomaterials

Polyamine-based Peptide Amphiphiles (PPAs) are a new class of self-assembling amphiphilic biomaterials-related to the peptide amphiphiles (PAs). ...

Synthesis and Characterization of 1,2-Dithiolane Modified Self-Assembling Peptides

This report focuses on the synthesis of an N-terminus 1,2-dithiolane modified self-assembling peptide and the characterization of the resulting ...

Methionine Functionalized Biocompatible Block Copolymers for Targeted Plasmid DNA Delivery

Reversible addition-fragmentation chain transfer (RAFT) polymerization integrates the advantages of radical polymerization and living polymerization. This ...