Controlling Interlamellar Spacing in Periodically Grafted Amphiphilic Copolymers

Chanda, Sananda and Ramakrishnan, S (2016) Controlling Interlamellar Spacing in Periodically Grafted Amphiphilic Copolymers. In: MACROMOLECULES, 49 (9). pp. 3254-3263.

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Abstract

We have examined a series of periodically grafted amphiphilic copolymers (PGACs) wherein pendant MPEG segments of varying lengths (TREG, 350, 550, and 750) were grafted at periodic intervals along a long crystallizable alkylene (C-20) backbone. The immiscibility of the alkylene and PEG segments, and the strong propensity of the alkylene segments to crystallize, drive these PGACs to self segregate by folding in a zigzag fashion and subsequently organize into a lamellar morphology, which was evident from DSC, SAXS, WAXS, and AFM studies; the interlamellar spacing was seen to increase linearly with MPEG length. Co-grafted PGACs, prepared by grafting a mixture of two different MPEGs (MPEG 350 and MPEG 750), also exhibited a lamellar morphology; interestingly, the interlamellar spacing was seen to depend only on the total PEG content, while the presence of a mixture of PEG lengths exerted little influence. However, a mixture of two homo-PGACs bearing either pendant MPEG350 or MPEG750 segments underwent macrophase separation, and interlamellar spacings corresponding to each were observed in the SAXS profiles. This study provides a new design for controlling the dimensions of the microphase-separated nanostructures at significantly smaller length scales (sub-10 nm) than is typically possible using block copolymers.

Item Type:	Journal Article
Publication:	MACROMOLECULES
Publisher:	AMER CHEMICAL SOC
Additional Information:	Copy right for this article belongs to the AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	15 Jun 2016 07:16
Last Modified:	15 Jun 2016 07:16
URI:	http://eprints.iisc.ac.in/id/eprint/53955

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