Exceptionally Fast Temperature-Responsive, Mechanically Strong and Extensible Monolithic Non-Porous Hydrogels:
Beata Strachota1, Adam Strachota1, Leana Vratović1
1Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovskeho nam. 2, 162 00 Praha, Czech Republic.
Gels (Basel, Switzerland)
|December 22, 2023
Summary
New hydrogels combine mechanical strength with rapid temperature response. These materials, based on poly(N-isopropyl-acrylamide) and hydroxypropyl methylcellulose, show potential for soft robotics and drug delivery.
Area of Science:
- Materials Science
- Polymer Chemistry
- Biomedical Engineering
Background:
- Developing advanced hydrogels with tunable properties is crucial for applications in soft robotics and drug delivery.
- Poly(N-isopropyl-acrylamide) (PNIPAm) hydrogels are known for their temperature responsiveness, but often lack mechanical robustness.
- Hydroxypropyl methylcellulose (HPMC) can be used to modify polymer networks, potentially enhancing their properties.
Purpose of the Study:
- To synthesize novel monolithic non-porous hydrogels with exceptionally fast temperature response and superior mechanical properties.
- To investigate the effect of intercalating HPMC into a divinyl-crosslinked PNIPAm network on hydrogel characteristics.
- To explore the potential applications of these tailored hydrogels in soft robotics and drug delivery systems.
Main Methods:
- Synthesis of divinyl-crosslinked PNIPAm hydrogels intercalated with HPMC.
- Extraction of non-fixed HPMC to create a 'template-modified' PNIPAm network with nano-channels.
- Characterization of mechanical properties (strength, toughness, extensibility) and temperature-response rate.
- Evaluation of drug delivery performance using Theophylline as a model drug.
Main Results:
- Synthesized hydrogels exhibited ultra-fast temperature response (as fast as 30 seconds) combined with high mechanical strength, toughness, and extensibility.
- The 'template-modified' PNIPAm network, featuring nano-channels from extracted HPMC, facilitated rapid water transport for quick deswelling.
- Micro-phase-separation, induced by high crosslinker and HPMC content, did not compromise mechanical or tensile properties.
- Tunable T-response rates were achieved by controlling synthesis heterogeneity, with faster-responsive gels suitable for soft actuators and slower ones for drug delivery.
Conclusions:
- The developed hydrogels offer a unique combination of rapid T-response and robust mechanical performance.
- The intercalation and subsequent partial extraction of HPMC is an effective strategy for creating advanced hydrogel materials.
- These hydrogels demonstrate significant potential for applications in soft robotics, drug delivery, and biomedical engineering.
Keywords:
cellulosedrug releasehydrogelspoly(N-isopropylacrylamide)semi-interpenetrating networkssmart materialsMore Related Videos
11:34Ultrathin Porated Elastic Hydrogels As a Biomimetic Basement Membrane for Dual Cell Culture
Published on: December 26, 2017
7.8K
08:17An Additive Manufacturing Technique for the Facile and Rapid Fabrication of Hydrogel-based Micromachines with Magnetically Responsive Components
Published on: July 18, 2018
7.2K
Related Concept Videos
02:34Polymers
The word polymer is derived from the Greek words “poly” which means “many” and “mer” which means “parts”. Polymers are long chains of molecules composed of repeating units of smaller molecules, known as monomers. They either occur naturally, such as DNA and proteins, or can be constructed synthetically, like plastics. They have varied structural characteristics, such as linear chains, branched chains, or complex networks, that contribute to the properties that they exhibit. Additionally,...
00:57Cationic Chain-Growth Polymerization: Mechanism
The cationic polymerization mechanism consists of three steps: initiation, propagation, and termination. In the initiation step of the polymerization process, the π bond of a monomer gets protonated by the Lewis acid catalyst, which is formed from boron trifluoride and water. The protonation of the π bond generates a carbocation stabilized by the electron‐donating group. In the propagation step, the π bond of the second monomer acts as a nucleophile and attacks the generated carbocation,...
01:03Step-Growth Polymerization: Overview
Step-growth or condensation polymerization is a stepwise reaction of bi or multifunctional monomers to form long-chain polymers. As all the monomers are reactive, most of the monomers are consumed at the early stages of the reaction to form small chains of reactive oligomers, which then combine to form long polymer chains in the late stages. Hence, the reaction has to proceed for a long time to achieve high molecular weight polymers.
Many natural and synthetic polymers are produced by...
Many natural and synthetic polymers are produced by...
01:20Types of Step-Growth Polymers: Polyesters
The introduction of polyesters has brought major development to the textile industry. The wrinkle-free behavior of polyester blends has eliminated the need for starching and ironing clothes.
Polyesters are commonly prepared from terephthalic acid and ethylene glycol; the crude product is known as poly(ethylene terephthalate) or PET. However, polyesters are synthesized industrially by transesterification of dimethyl terephthalate with ethylene glycol at 150 °C. The two reactants and the polymer...
Polyesters are commonly prepared from terephthalic acid and ethylene glycol; the crude product is known as poly(ethylene terephthalate) or PET. However, polyesters are synthesized industrially by transesterification of dimethyl terephthalate with ethylene glycol at 150 °C. The two reactants and the polymer...
01:13Olefin Metathesis Polymerization: Overview
Recently, the development of olefin metathesis polymerization advanced the field of polymer synthesis. Simply put, the reorganization of substituents on their double bonds between two olefins in the presence of a catalyst is known as the olefin metathesis reaction. The use of metathesis reaction for polymer synthesis is called olefin metathesis polymerization.
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists of a...
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists of a...
01:16Olefin Metathesis Polymerization: Ring-Opening Metathesis Polymerization (ROMP)
Ring-opening metathesis polymerization or ROMP involves strained cycloalkenes as starting materials. The mechanism of ROMP proceeds by reacting cycloalkene with Grubbs catalyst to give metallacyclobutane intermediate which undergoes a ring-opening reaction to form new carbene. The new carbene reacts with another molecule of cycloalkene. Repetition of these steps leads to the formation of an unsaturated open-chain polymer product. All these steps are reversible, however, relieving the ring...