Poly(N-isopropylacrylamide) (PNIPAM) is never hydrophobic

Pelton, Robert

doi:10.1016/j.jcis.2010.05.034

Cited by 262 publications

(242 citation statements)

References 23 publications

Supporting

Mentioning

227

Contrasting

Unclassified

Order By: Relevance

“…From 33 to 50 °C, particle size increase is probably related to an aggregation process undergone by the modified MNPs, where solute-isoPr group interactions are energetically more favorable for isoPr groups in a polymer rich environment compared to isoPr groups in water. 28 This effect would be similar to the aggregation process reported for other hybrid materials with a different polymer where a thermally triggered hydrophilic-to-hydrophobic phase transition occurred. 29 It is worth mentioning that the particle sizes here reported are considerably bigger than those previously reported by others authors.…”

Section: Study Of the Thermo-responsive Properties Of Mnps-memo-pnipasupporting

confidence: 80%

Synthesis and characterization of thermo-sensitive magnetic maghemite nanoparticles

Cappelletti¹,

Paez²,

Strumia³

2011

Arkivoc

View full text Add to dashboard Cite

The modification of magnetic nanoparticles (MNPs) with a thermo-sensitive organic shell of poly(N-isopropylacrylamide) (PNIPAm) is reported. The surface of maghemite MNPs was modified in two steps: firstly, using a silane coupling agent and leaving vinyl pending groups on the MNPs surface; and secondly, grafting PNIPAm chains from the modified MNPs via a free radical polymerization. The results indicate that the method developed here for the modification of MNPs is an effective way of synthesizing thermo-responsive MNPs. They present a magnetic behavior due to the maghemite core and a thermal response based on a deswelling/swelling of their polymeric shell (PNIPAm).

show abstract

Section: Study Of the Thermo-responsive Properties Of Mnps-memo-pnipasupporting

confidence: 80%

Synthesis and characterization of thermo-sensitive magnetic maghemite nanoparticles

Cappelletti¹,

Paez²,

Strumia³

2011

Arkivoc

View full text Add to dashboard Cite

show abstract

“…There is limited consistency in the literature on the use of the terms hydrophobicity or hydrophilicity when referring to polymers. 40 Therefore, in the context of this work, we decided to use the more general term "degree of hydrophilicity". Five sets of polymers based on NIPAM (N1-N5), NPAM (N6-N10), NAPr (N11-N15), or combinations of NIPAM-NAPr (N16-N20) and NPAM-NAPr (N21-N25) were synthesised with percentages of the crosslinker MBA ranging between 10% and 50%.…”

Section: Thermoresponsive Nanogelsmentioning

confidence: 99%

An l-proline based thermoresponsive and pH-switchable nanogel as a drug delivery vehicle

Salinas

Resmini

2018

Polym. Chem.

View full text Add to dashboard Cite

The synthesis and characterisation of a novel dual stimuli-responsive nanogel, based on thermoresponsive N-n-propylacrylamide and an L-proline based monomer acting as a pH-switcher, is reported here. The effect of the crosslinker/co-monomer ratios was studied to demonstrate the relationship between the chemical structure, degree of hydrophobicity and physico-chemical characteristics of the nanogels. Tailoring of the thermoresponsive properties was achieved by altering crosslinker N,N'-methylenebis (acrylamide) content between 10 and 50 mol%, in combination with three thermoresponsive monomers N-n-isopropylacrylamide, N-n-propylacrylamide and N-acryloylpyrrolidine. A library of 25 different combinations of monomers and crosslinkers was obtained and characterised by dynamic light scattering and UV-Vis spectroscopy. The nanogel based on N-n-propylacrylamide and 10 mol% crosslinker was then co-polymerised with an L-proline based monomer to introduce a pH-switch. This nanogel was obtained with <10 nm particle size and a VPTT ca. 43°C, and was used to demonstrate a drug delivery capability using Nile Blue A as a model drug. Detailed studies demonstrated maximum drug release at lower pH and 43°C, thus confirming the dual stimuli switch.

show abstract

“…51,52 The effective amount of NIPAM incorporated in the network was 22% (w/w) and the average diameter of the particles was 1.8 mm according to scanning electron microscopy (dry state), DLS and confocal scanning laser microscopy (CLSM) in solution. The incorporation of NIPAM induces a thermoresponsive deswelling of the PVA-based microgel network above a VPTT of about 33 C to achieve a new type of switchable microgels for drug transport. 51 Data on the effect of NIPAM content on the swelling degree of the particles are provided in the ESI (Table S1 †).…”

Section: Methodsmentioning

confidence: 99%

“…Above the VPTT the PNIPAM chains coil up, the particles deswell and the solvent is mainly released due to energetically more favourable internal interactions within the polymer network. [31][32][33] The result is a temperature dependent change in optical and mechanical properties of the microgel 7,8,31,34 and a strong thermophoretic effect.…”

Section: Introductionmentioning

confidence: 99%

Quantitative X-ray microscopic analysis of individual thermoresponsive microgel particles in aqueous solution

et al. 2016

View full text Add to dashboard Cite

High resolution scanning soft X-ray transmission microscopy (STXM) has been employed to investigate individual thermoresponsive microgel particles in aqueous environments. STXM generates 2-dimensional projections with spatial resolutions in the regime of a few 10 s of nm. In the present study we are able to regain a 3D representation of the investigated specimen and observe the deswelling of the microgel particles upon heating, thus offering insight into the thermoresponsive behaviour of individual differently sized particles. We employ a 2-shell model that is able to derive the radial concentration profile of individual microgels particles and thus serves as a complementary method to scattering experiments that average over all particles. Furthermore, we are able to detect the different deswelling behaviour of the particle interior and its interface to the water environment.

show abstract

Poly(N-isopropylacrylamide) (PNIPAM) is never hydrophobic

Cited by 262 publications

References 23 publications

Synthesis and characterization of thermo-sensitive magnetic maghemite nanoparticles

Synthesis and characterization of thermo-sensitive magnetic maghemite nanoparticles

An l-proline based thermoresponsive and pH-switchable nanogel as a drug delivery vehicle

Quantitative X-ray microscopic analysis of individual thermoresponsive microgel particles in aqueous solution

Contact Info

Product

Resources

About