# Amylopectin Copolymers Grafted with RAFT-Obtained Synthetic Polymers: Synthesis and Aqueous Solution Behavior

## TL;DR

This paper describes the synthesis of hybrid copolymers using amylopectin and synthetic polymers, which respond to stimuli like temperature and pH.

## Contribution

The study introduces a novel method for creating graft copolymers with amylopectin and stimuli-responsive synthetic polymers.

## Key findings

- Novel graft copolymers AMP-g-PNIPAM, AMP-g-PDMAEMA, and AMP-g-POEGMA were successfully synthesized.
- The copolymers showed responsiveness to pH, temperature, and ionic strength in aqueous solutions.
- Self-assembly behavior was observed based on protonation and deprotonation equilibria.

## Abstract

According to the requirements of modern society for durable
biomaterials
with multiple functionalities, the principal target of this study
was to apply the “grafting to” scheme on the synthesis
of several hybrid copolymers based on amylopectin (AMP) and poly­(N-isopropylacrylamide) (PNIPAM), poly­(oligo­(ethylene glycol)
methyl ether methacrylate) (POEGMA), and poly­(2-(dimethylamino) ethyl
methacrylate) (PDMAEMA) as synthetic polymer components, thus obtaining
hybrid copolymers responsive to different stimuli, such as temperature,
pH, and ionic strength. The synthetic polymers were synthesized by
reversible addition–fragmentation chain transfer polymerization
and contain reactive carboxyl groups attached to one end of the polymeric
chains. The successful synthesis of novel graft copolymers AMP-g-PNIPAM, AMP-g-PDMAEMA, and AMP-g-POEGMA was confirmed by ATR-FTIR and 1H NMR
spectroscopies, by evidencing the appearance of new aliphatic ether
bonds as a consequence of covalent grafting of the synthetic polymers
onto the AMP chains. The pH, temperature, and ionic strength responsiveness
of the newly obtained copolymers’ aqueous solutions were followed
by dynamic and electrophoretic light scattering analysis, revealing
the intra/interchain self-assembly depending on the ionizable groups
present in their structure, according to their protonation or deprotonation
equilibria.